pls be evil all the way and not some half ass later
Judging from the ending scene in chapter 21, i think it's safe to say there's a reason Abi acts like a jerk. I don't think she's going to be full evil, not that she really ever was, she just has resentment for those who get lucky specifically.
My guess is her childhood friend stopped being friends with her because she thinks she only made it big because she got lucky and that's why she's so hard on Fuwari and Junna.
Either that or she's jealous of her friend who got lucky, but i dont think that's the case because Abi is already a top idol.
Unless you're referring to Junna, in which case it's pretty obvious she's going down the "scumbag turned revered idol by sheer accident" route, what with her getting genuinely emotional during the first elimation and such.