|The following is based on information from Van Buren design documents and is not canon.|
To lead the tribe, the PC must defeat Kurisu in three different challenges: strength, agility, and combat (unpowered weapons only). They occur right after each other, so any damage you've suffered during the first two trials is still in effect for the last trial. Once you defeat her (it's not to the death) you're in charge, though it will take some time for the tribe to adjust (you lose some status for challenging an existing strong and well-liked leader, but can make up for it with your actions).
Character type completion breakdown
- Science Boy - Drug himself up or poison her secretly before the competition. Problematic, though, as she has the right to delay the challenge by 5 days. He could also drug her mind (with reverse-Mentats or something) and then try the ChaBoy route.
- Charisma Boy - Convince her to step down and let Chagas lead, possibly by turning her away from her bitterness about not being rescued by her family, possibly by some sort of romantic involvement. This also works to help convince her to become your CNPC. He could also "psyche her out" beforehand, making her a little shaky in her reactions.
- Stealth Boy - Plant some things in the tent and elsewhere in the town to incriminate her or otherwise turn the tribe against her, or sabotage the strength and agility tests.
- Combat Boy - Ought to be able to beat her down with sufficient technology and maybe access to some drugs for the other two tests.
In the design document, this quest is marked out, suggesting that this quest was canceled and wasn't going to appear in the game.