Zilean is a support-oriented AP carry. While he does not have the damage output or the hard CC of many other AP carries, he specializes in providing to his team mobility, utility, and possibly one of the most annoying ultimates in the game to play against. While previously thought overpowered--subsequent nerfs, both to himself and to some of the popular tanky DPS champions he is designed to back up have taken him off the radar a bit. However, he is still an extremely solid AP carry on the right team, and is a favorite of several of the best AP carry players in the game.
Basics
+ Show Spoiler [Patch Notes] +
V1.0.0.118:
Fixed a bug where Time Bomb didn't show its damage type in death recap.
V1.0.0.113:
*Time Bomb:
Mana cost increased to 70/85/100/115/130 from 60/75/90/105/120.
Base damage reduced to 90/145/200/260/320 from 100/155/210/270/330.
*Chrono Shift:
Base health upon revival increased to 600/850/1100 from 500/750/1000.
Ability power ratio reduced to 2 from 3.
Buff duration reduced to 7 from 10.
Will now always activate after Undying Rage but before Guardian Angel and Rebirth.
V1.0.0.112:
Fixed a bug where the particle on Time Warp would not persist through the full duration of the movement speed modifier at later ranks.
V1.0.0.111:
Base magic resistance reduced to 30 from 35.
V1.0.0.109:
*Chrono Shift duration reduced to 10 seconds from 13.
V1.0.0.103:
*Chrono Shift now removes most positive buffs from your champion when it activates.
V1.0.0.101:
*Chrono Shift:
Duration reduced to 13 seconds from 15.
Cooldown increased to 180 seconds at all levels from 180/160/140 seconds.
V1.0.0.97:
*Chrono Shift's buff icon will now display a timer for when the buff will fade.
V1.0.0.96:
Fixed a bug where replacing an enemy Time Bomb wouldn't cause the deactivation explosion.
Fixed a bug where replacing your own Time Bomb caused more damage than intended from ability power.
Fixed a bug where the Time Bomb explosion particle occasionally showed over fog of war.
Fixed a bug where Time Bomb would occasionally remain on dead units.
V1.0.0.87:
Clarified the tooltip of Rewind to remove some redundant information.
V1.0.0.86:
*Time Bomb:
Ability power ratio decreased to .9 from 1.1.
It now ticks 3, 2, 1 additional damage before the bomb explodes. This will trigger calls for help.
V1.0.0.79:
Fixed a particle issue with Time Bomb.
V1.0.0.74:
*Rewind cooldown reduced to 18/15/12/9/6 from 30/28/26/24/22, but will no longer affect itself.
V1.0.0.72:
*Time Warp:
Movement speed modifier reduced to 55%, from 65%.
Haste effect is now a multiplicative movement speed modifier.
Duration reduced to 2.5/3.25/4/4.75/5.5, from 3/4/5/6/7.
Range increased to 650 from 600.
*Time Bomb range increased to 650 from 600.
*Chrono Shift range increased to 900 from 600.
V1.0.0.70:
*Rewind cooldown changed to 30/28/26/24/22 from 38/34/30/26/22.
*Time Bomb:
Damage increased to 100/155/210/270/330 from 90/145/200/260/320.
Mana cost decreased to 60/75/90/105/120 from 70/85/100/115/130.
*Time Warp:
Mana cost decreased to 100 from 110 at all ranks.
It now applies a multiplicative movement speed slow rather than additive.
V1.0.0.63:
Basic attack projectile speed increased to 1200 from 900.
V1.0.0.61:
*Time Bomb no longer detonates if the buff is cleansed.
V0.9.22.16:
*Chrono Shift:
Increased Cooldown from 160/140/120 to 180/160/140.
Fixed a bug which caused issues with Anivia's Rebirth.
V0.9.22.15:
*Rewind cooldown modified from 40/35/30/25/20 to 38/34/30/26/22.
*Time Warp can no longer target Minions and Monsters.
*Time Bomb Damage increased from 80/140/200/260/320 to 90/145/200/260/320.
V0.8.22.115:
*Time Warp Haste / Slow increased from 60 to 65% due to movement speed soft capping.
*Recall no longer causes or is affected by global cooldown.
+ Show Spoiler [Stats] +
Health: 380 (+71)
Mana: 260 (+60)
Damage: 48.6 (+3)
Attack Speed: 0.625 (+2%)
Range: 600
Health Regen.: 4.6 (+0.5)
Mana Regen.: 4.45 (+0.45)
Armor: 6.75 (+3.8)
Magic Res.: 30 (+0)
Mov. Speed: 310
Heightened Learning (Innate): Increases the experience all allied champions gain by 8%. This is not in effect while Zilean is dead.
Time Bomb (Active): Zilean places a time-delayed bomb on a target. After 4 seconds the bomb will detonate, dealing magic damage to all surrounding enemies. The bomb will detonate immediately if the holder dies or another bomb is placed on them. Enemy holder will take 1, 2, 3 extra true damage gradually before the detonation.
Cooldown: 10 seconds
Range: 700
Explosion radius:
Cost: 70 / 85 / 100 / 115 / 130 mana
Magic Damage: 90 / 145 / 200 / 260 / 320 (+0.9 per ability power)
Rewind (Active): Reduces all of Zilean's other cooldowns by 10 seconds. Rewind does not affect itself.
Cost: 50 mana
Cooldown: 18 / 15 / 12 / 9 / 6 seconds
Time Warp (Active): Zilean slows an enemy champion's movement speed or increases an allied champion's movement speed by 55% for a few seconds.
Cost: 100 mana
Cooldown: 20 seconds
Range: 700
Duration: 2.5 / 3.25 / 4 / 4.75 / 5.5 seconds
Chrono Shift (Active): Marks an ally champion or himself with a protective time rune for 7 seconds. If the target takes lethal damage during this time, instead of dying, they will be untargettable and remain in stasis for 2 seconds and then they return to life regaining health.
Cooldown: 180 seconds
Cost: 200 mana
Range: 900
Health Gained: 600 / 850 / 1100 (+2.0 per ability power)
Summoner Spells
Flash is pretty much mandatory. Of the escape summoners, it's pretty clearly the most sensible one to take on Zilean. As for the other summoner slot:
Ignite/Exhaust - Combat utility summoners. These are the two most common summoners I run in the 2nd slot, and which one I choose is generally dependent on which is more useful based on the enemy team. Ignite lets you threaten some pretty surprising amount of burst in lane (though it's obviously taken against targets you'll need the anti-heal to push a kill against), and Exhaust is actually really useful for keeping yourself from getting chased too far out of fights (more on that later).
Cleanse/Teleport - I usually don't take these, but they can have some situational use. Teleport can set up some pretty sick turnarounds in early-midgame teamfights and can be useful in lane to buy/heal/restore mana, but I feel like you don't really need it lategame, as being able to perma-E with blue buff gives you plenty of map mobility without using a summoner spell. Cleanse could be useful if you're dealing with a lot of troublesome CC, though I think Zilean should generally be positioned in such a way that he can avoid most of that. Zilean ulti is also not like Janna ulti where if a bad initiate happens, you'd want to cleanse-ulti right away or something--seeing as unlike Janna ulti, Zilean ult can't really save your whole team.
Masteries
9/0/21. Zilean is a strong laner, so generally defensive masteries are not necessary. I take Greed over the 3rd point in Haste because I don't feel Zilean needs the movespeed, but either way is fine. Obviously get the summoner spell masteries for Exhaust or Teleport if you're running either.
Runes
Runing on Zilean is fairly flexible. As mentioned, he is a strong laner, and he doesn't really have any huge holes that can be filled efficiently by runing for them. As such he can be runed for early game dominance, survivability, or mid- or late-game damage, depending on your playstyle. Some rune sets that I have used/played against:
MPen marks, choice seals, AP/lvl glyphs, Flat AP quints -- Standard caster runes. I use these most often. They work on most other casters, and they're a pretty solid set to default to on Zilean, especially given his great ratios.
MPen marks, choice yellows, MPen glyphs, MPen quints -- Mass MPen page to push early dominance against weaker laners. The 19 MPen obviously hits pretty hard early on, but really shines after your Sorcs-in particular if you're facing targets that have runed or masteried MR sources (13 MR from runes or 6 MR from masteries). I've also seen similar pages using flat AP blues/quints-the goal is the same, but it pushes its advantage in a different level range: the AP is stronger early levels, when you don't have other penetration sources to go with your runed MPen, and your base damage is low, while the MPen is stronger in tandem with Sorcs, and when you're working with the high base damage of ranks 3-5 of Time Bomb. Personally I prefer the MPen, since in that level range you can play more aggressively behind the second chance your ult gives you, and you have Catalyst/blue buff regen to back up your bomb spam, but it's up to playstyle and matchup.
MPen marks, HP/lvl yellows, MR blues, AP quints -- A much more defensive rune set. I'd consider this rune set against someone like, say, Annie. Generally, I think Zilean is a strong enough laner that smart E/ulti use can avert most deaths, but this more defensive rune set is reasonable if you're worried about the risk of dying inside a stun without getting a chance to ulti or something.
Skill Order
QWQEQR, R>Q>W>E. You can shift the first point of E earlier if you consider super-early jungle/roaming ganks to be a big enough threat to warrant reducing your laning power. Midgame you can also consider leveling E a bit with W if mana is tight (e.g. your jungler hogs their blue buff).
Items
There are generally two main sets of items to build into for laning, as on other AP carries--Catalyst, or Doran's Ring stack. Doran's Rings give you cost-efficient AP/mana regen, and allow you to pressure super hard--30-45 AP on a 0.9 AP ratio nuke really starts to sting once you get a few ranks in it. Catalyst eschews the ability to pressure, in exchange for HP/Mana sustain, which lets you play more attrition or farm-based lanes. What item I start generally is based on which of those two setups I expect to transition to. Boots+3pot is probably the most well-rounded opening. It gives you the most pots to work with, the movespeed advantage for bomb harass, and lets you transition smoothly into either early-game setup. Sapphire Crystal+2pot is weaker than boots, and somewhat commits you to building Catalyst, but it lets you squeeze it out that much faster, which can be important in certain matchups. Doran's Ring lets you hit like a truck early levels, but because you have no potions, you have to be mindful that a bad trade or a gank will probably force a bluepill out of you.
Get Sorc Boots sometime midgame (or Mercs if you feel you need them), but do not feel rushed to get them. Zilean is definitely a champ that can afford to stay on Boots 1 for a long time if he needs to. I generally do not consider CDR boots as an option, since you should be hogging blue buff on Zilean. I can see them being useful if you're playing with a 2nd AP champion that is even more of a blue hog (e.g. Anivia), but I probably would also be against picking Zilean at that point, since Zilean shines much more on a team with a tanky DPS champion than with a second AP. Even if you got Catalyst, don't be afraid to pad your inventory with a DRing or two if you bluepilled and don't have the cash for anything else--the HP, mp5, and AP stay useful all game. Likewise, even if you started with DRing stack, you may still want to opt for Cata->Rod if it seems to fit the game.
Midgame you want to consider whether you plan on getting Rod of Ages and Deathcap after, or going straight for Deathcap. Rod is extremely good on Zilean, as he can make use of the mana and HP very well, but it takes quite a while to charge, and delays your Deathcap. In general, Rod is a great buy if you got pretty good farm early on, but you should use good judgment on whether it will delay your damage too long, and whether you should just skip it for Deathcap (it's sort of hard to explain how to make that decision--I usually just play it by ear).
Post-Deathcap your item options are flexible and similar to other AP carries. BVeil is an MR option if you've got your Catalyst left over, as is Abyssal if you don't. Zhonya's gives you armor, and the active is good for buying you a few seconds' breathing room. Get Void Staff when it's needed. Just generally tailor what you get to how the game is playing out, and make sure you've got money for wards and Blue Elixirs.
Playstyle
Laning
Take a solo lane, always. Some people advocate duo lane Zilean, but I really don't. In a nutshell, duo lane Zilean ends up with very little AP, because he spends the whole game building a blue buff (40% CDR and mana regen) for himself because he's a support. As such, it throws away one and a half skills (your bomb becomes useless because you don't get to itemize toward it's scaling, and as such, reducing it's cooldown isn't worth a lot). On top of which, he lacks healing/sustain, and his harass gives your opponents total control of where the creeps meet, so he's not really a great babysitter. Mid is ideal, but top is somewhat manageable. I dislike top lane because Zilean can't really match the sustain of most common top laners right now, whereas he's more in line with the common mid lane AP champs.
Zilean is a good laner. He is one of the 5 champions in the game with a natural 600+ attack range (Anivia and Ashe have 600 as well, Annie has 625, Caitlyn has 650)--allowing him to lasthit safely and harass with autoattacks without risk of retaliation, while also being one of the only champs in the game with a 700 range non-skillshot nuke. He is hard to gank effectively early because of his E, and extremely hard to gank effectively after 6 because of his ultimate.
You are strong at level 1, and stronger at levels 2 and 3. Your burst at level 3 outdoes a lot of other laners (2 2nd rank nukes, as opposed to a 2nd rank nuke and a 1st rank nuke from any other AP carry), so you can abuse this fact to bully people at those levels. At levels 4 and 6, your burst doesn't improve like most other AP carries, so at those levels, enemies tend to catch up. They do, however, make you considerably harder to gank, so trades at those levels can still be advantageous to you. Additionally, E makes it so an opponent has to commit quite hard if they want to retaliate against your Q harass. You can use this to widen the health disparity you created at earlier levels (or to bait a good gank from your jungler), but be careful managing your mana. Zilean's main weaknesses are his lack of natural means of sustain and his relatively high mana costs. As such, he can lose lane to champions that push lane super hard (he doesn't have a great means of lasthitting under tower, and using bombs to clear creeps is extremely taxing on your mana), and champions that have strong health sustain or mana-efficient counter-burst and can weather the storm of your level 1-3 burst. Champions with both of these qualities such as Morgana or Galio tend to be hard matchups for Zilean. Catalyst helps this, but nevertheless smart mana management is important, and don't be afraid to mass-pot for HP or some mana (particularly if you're skipping Cata). At worst, you might want to bring Teleport, or try to get an early blue buff from your jungler.
You (and your lane opponent) should be mindful of how much damage your bombs do, and of any creeps that are below that amount. Through the threat of a double bomb, you can use these minions as a means to extend your effective range. If your opponent strays too close to them, you can ping a double bomb on one of the low-HP minions, catching your opponent in the damage at effectively 800+ range. These also tend to have a big psychological effect on your opponent--losing 1/3-1/2 of his life in a single hit tends to be pretty intimidating, even though as Zilean, you have no real followup for another 10 seconds. This is especially effective against melee laners (as in order to lasthit YOUR low-HP melee creeps, they have to get close to theirs), and becomes quite a pain at the level where your bombs can 1-shot ranged minions (generally level 7 or 9, depending on your items/runes).
Get blue buff as early as your jungler will allow. The mana will let you harass the opposing laner extremely frequently, and push the creep wave back if they're pushing hard against you. When you've forced them back, you can push out the lane and abuse the mobility that E/W gives you to go help out other lanes. You can often shove the lane hard, get a good gank in, and then return to lane before you lose too many creeps to tower. As your baseline burst starts to drop off a bit compared to other AP champs, this tends to be a good way to assert your lane control, as a smart opponent is unlikely to die simply to your QWQ-Ignite burst.
Teamfighting
Generally, if you are teamfighting with Zilean, you can expect the other team to send someone to try and do what Warwick did in this video:
http://www.own3d.tv/video/136831/aAa_vs_Team_SoloMid__Semi-Final_Game_2
They will attempt to chase you out of the fight, and disrupt your ability to support your team. While getting someone to actually be able to kill Zilean is difficult, Zilean's middling damage output means that if he doesn't get backup from his team, it can take quite a long time for him to handle the threat on his own (and could involve him getting chased halfway across the map from his team, as happened to Regi in the video), effectively marginalizing his contribution to the real teamfight. They will attempt to get you to use single-target bombs (drastically reducing their effectiveness) and repeated slows on the person chasing you (less effective than perma speed/slowing up to 2 people elsewhere in the fight) or, in the worst case, get you to blow your ultimate on yourself. This is where Exhaust tends to be useful, as it buys you a few seconds where you can position yourself and cast without eating too much damage from the guy trying to chase you down.
Your early positioning in the fight is critical. While generally, you will be in the backed-up position that the AP carry normally occupies, this can be exceedingly awkward when you have to move to support your tanks and tanky DPS. As such, flanking with your tanky DPS is sometimes reasonable, going in after them to back them up, allowing you to push continual damage onto the enemy carries while staying in a place that's hard to reach for the enemy tanks/anti-carries. Note that this will drastically reduce your ability to reach and support other targets in the fight, and can be exceedingly dangerous vs. high-mobility anti-carries like Akali.
Ultimately, you will have to do some kiting/weaving in and out of fights, especially since your best friends are the guys that want to dive in balls-deep. Make sure you get that speed/bomb on the tank/tanky DPS just as the fight starts, because you don't know when you'll get another good one. Generally speaking, placing bombs on the enemy probably won't be the most reliable place to bomb, and doesn't make good use of the delay, or the fact that they can get carried in on something else. Teammates are pretty good for getting bombs to good targets (in particular melee ones, as they will be either in the middle of multiple people, or trying to go for an enemy squishy--both good places for your damage to go). Minions also work as good bomb targets, particularly if you can squeeze off a double bomb on an enemy minion coming through the fight.
Your ideal ult target is a tanky DPS, but pretty much anyone can be a good target depending on the situation (especially since, if you're farmed, your ult is a full heal on everyone). You want to ult the person that will have the most effect in the fight from living. Will the carry be able to stay alive to do damage after your ult? Does the tank/support/AP carry have critical spells un-cast before they died (using your ult to get a use out of someone else's ult AND save their life is generally worth it)? Worst comes to worst, just use it to save whoever. It's better to save somebody than to not save somebody, especially since lategame, your ulti has effectively a 30 second cooldown.
Special mention for Zilean's best (duo queue) friends
+ Show Spoiler +
Zilean shines as an AP carry when paired with tanky DPS. His damage, while not subpar, is decidedly mediocre. He can kite well, but his E used purely as a CC is underwhelming compared to the hard CCs/AoEs available to other AP carries. Particularly if you did not get super-farmed early-midgame, your strength as an AP carry will inevitably diminish lategame. And his ultimate, while game-changing nonetheless, does not nearly have as huge an impact when used on a squishy AP/AD carry (who won't really gain that much time alive when they have no resistances) or a tank (who will probably have some/most of his strong skills on cooldown, and not create much of a splash being alive again). Tanky DPS champs get the most out of Zilean's ult. They have the mitigation stats to make the revive a pain to deal with, while also not being ignorable, given their damage output. They also generally maximize the use on Zilean's other spells as well--their placement in a fight is generally where Zilean wants his bombs to blow up (on top of squishy carries), and they can utilize Zilean's speed boost throughout the entire fight.
Two examples for what Zilean can do for tanky DPS:
Zilean takes the aspects of Irelia's kit that are already strong, and pushes them to absurd levels. Low cooldown ult that makes her hard to kill? Add a second one, and she's invincible (I've literally had fights where, with both of us on 40% CDR, we were able to rotate Irelia Ult->Zilean Ult->Guardian Angel->Irelia Ult->Zilean Ult). Some of the strongest midgame physical-damage burst in the game? Pop a bomb or two on her head to add even more (magic) damage to it, giving an extremely hard-to-counter mix of magic, physical, and true damage. Great movespeed and ridiculous diving range? Add a 55% movespeed boost going in, and diving past two towers-worth of distance becomes easy. There's a reason why Reginald and Chaox love running this pair, and it's not just because they're good at the respective champions.
While Zilean augments the strengths of Irelia's kit and pushes them to the extreme, with Olaf he shores up his weaknesses and makes him a well-rounded killing machine. The speed boost gives Olaf a legitimate gap-closer (whereas on his own, he relies on being able to land his axe on his target), the bombs, as with Irelia, augment his damage, giving him a mix of physical, magical, and true damage. One of the great benefits of having Zilean with Olaf, however, is that it really allows Olaf to put his passive to use. Normally, Olaf doesn't get to push his passive to the absolute limit, as the risk of dying comes with the attack speed boost. However, with Zilean ult behind him, Olaf can literally fight to 0 HP. With enough resistances, Olaf can be hacking away for several seconds with two Recurve Bows' worth of attack speed, which, with his natural AD steroid, will just wreck people in fights.