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1. Kerrigan purposely let the artifact de-infest her because she knew she has to be stronger than she was (more on that later).
2. She knows Jimmy won't kill her, and as cunning as she was in Brood War she tricked him by having the "HotS" for him and saying she has forgotten what she did as the queen btch of blades.
3. She convinced Jimmy to work with her to get rid of Mengsk together, since both of they have a common enemy. Jimmy agreed.
4. While doing this, Izsha, who stores Kerrigan's memory and plans executed the operation. Gave orders to the brood mothers mission objectives, (1) find more critters, assimilate, learn and evolve. Until they are ready to go to Zerus. And (2), act like they hate each other by wanting to lead the whole Swarm to confuse the enemy. (3) Orders Zagara to "hunt" Kerrigan down, because she is the 2nd strongest Zerg in the Swarm. Having the "ambition" to be the ruler.
5. So while Kerrigan and Raynor Raiders are being caught in between by both Zagara and Dominion (Nova's squad, more screen time instead of just showing up at the beginning) for a few missions. At some point, she has to let herself get separated with Jimmy. And gets "captured" by Zagara in the process, Dominion got their hands on Jimmy too. Raiders had no choice but to pull back.
(along the missions, Kerrigan can still keep in contact with Izsha with the missions and Abathur on the evolution psionic-ly )
6. But Zagara, being overly ambitious gets over her head. Kerrigan fights with her Swarm and wins showing who's the true Queen. After that, they traveled to Zerus.
7. Frees Zurvan, gets into the first Spawning Pool to reinfest herself. Becomes Primal Zerg Queen. Kills some Primal Zerg pack leaders and Zurvan. Dehaka joins. Well you know how it goes.
8. Meanwhile, Zeratul went to rescue Jimmy, another mini protoss campaign. Reached his cell and Jimmy asked for his help to go find Kerrigan, zeratul finds him at a weak state (tortured), he tried to get him out, but was ambushed by spectres.
9. Jimmy knew he was only pulling Zeratul back, so he asked him to forget abt him and find Kerrigan. Zeratul looking for a way out, and suddenly felt the same disturbed feeling like he did with his first encounter with Duran back in BW. He went to investigate further and ninja his way till they reached the bottom level and was horrified to see the same things he saw, hybrids.
10. Greeted by Narud, boss fight level. And after defeating him, a cut scene of both zeratul and narud fighting each other, narud mocking him talking about Amon, and how the universe is doomed bla bla. Then suddenly got interrupted by an alarm of sudden zerg attack, zeratul too severely injured to fight any longer, so he decided to escape with narud (in his fallen xel naga form) chasing him with a pair of hybrids. When reaching to end (cut scene), both were greeted by Kerrigan and got their ass kicked even more (caught by surprise by her appearance). narud got injured and disappeared, while zeratul lays unconscious. She then left him lying and facility explodes.
11. Kerrigan's next step, take back char. same everything including cut scene.
12. After char, went back to the leviathan. got contacted by Jimmy (webcam device-like found by one of her brood mother like in the campaign at some point) and was confronted on her betrayal. She then admits that she was just playing along during in WoL, telling him that the reason why she disappeared for 4 years, was becoz she studied the how the artifacts actually worked and also origins of the Swarm and discovered of the Primal Zerg existence. While at the same time, strengthening her Swarm. she knew what the artifacts could do before he was collecting them, and also she only let them took it just to activate it for her and take her form of essence away, and play a fool out of him so that no one can suspect of her true intention. Zeratul was also there in the Hyperion listening, and urged Jimmy it's alright, as it was to fulfill the prophecy. Kerrigan got irritated by his bullsht prophecy and told him off. It was also revealed that valerian did in fact worked with kerrigan, because he wanted to overthrow his father, and he knew that only kerrigan can destroy mengsk. and that is how he got tychus to convince jimmy to collect the artifacts for the mobieus foundation. however he had no clue of narud being a shapeshifter. narud did well in hiding himself and worked on the hybrids. Valerian also pleaded her to give him more time to evacuate the citizens. kerrigan refuses at first then said "just dont get in my way", and acknowledged him that he's not as horrible as his father. then signs off.
13. zerg invasion, everything same (except Jimmy didnt come) until the ending scene. Kerrigan entered Mengsk's room and talked for awhile, saying there's someone who was waiting for her. Kerrigan then saw Narud, and immediately sense he wasnt human. Narud then greeted her as if he knew her, confusing her for awhile. Narud then changed his appearance to Duran and mocked her on her rebirth to the swarm (refer to dark origins mission transcript) actually quicken his research progress. This angers her, and both fought in the true final battle (micro battle with some zerg forces vs him and 2 hybrids).
14. After Kerrigan won the tough fight and injured Duran badly, Mengsk (surprisingly didnt ran away, coz he believed Duran could beat her and wanted to witnessed it) then tried to escape but Kerrigan quickly stabbed him with her wing claws then proceeded to have her vengeance, killing off Mengsk the same way that Zagara injected a larvae into Lassara's body (my version), making him suffer and die a gruesome death with a new brood mother larvae popping out of his chest (alien style). Duran quickly took this chance and disappeared, whispering from the void that Amon will soon come and finish everything. Kerrigan looks into the sky with her Swarm going back to the leviathan, with a tired but yet peaceful face expression. screen fades to black and she ponders of the prophecy that Zeratul spoke with her narration, and actually was considering that Amon is indeed her true enemy. The end.