Any Yaoi/Shounen Ai with the second MC as the endgame (like he was not the first to appers)?
if the spoilers are right this one will fit the description:
https://www.mangago.me/read-manga/the_snake_that_swallowed_the_pomegranate/ (they both the endgame)
My theory that the powers are giving (and taken by) death.
First Katou tries to kill himself and its the first time we see the powers. Then kills Oda by assuming control of the driver's body, the driver js killed too but not essentialy by Katou who have powers until Oda kills him (essentialy the sexual assault) so his "after life in life" powers are taken. I am really preaching but I also have strong feelings for this story