TVD became the Damon show where everyone just propped him and excused him of his shit behavior. It got annoying af!!
I enjoy Bonkai dynamic partly because of that and the thing is we never got that resolution or closure (except in fanfics) 😭
I do think Bon has that darkness in her and that comes out when he is around. When she first meets him and discovers he does not know the spell she kills him. She doesn’t know that he can come back to life? I don’t think that was established at all tbh 👀 and from what we saw with Bon in past S1-5 she never was like that. Yeah she took down bad guys but she never just murdered someone that quick. Also even though their season 8 reunion was short you see her smile and get pleasure out of leaving him in a 2018 prison world 💀😆
The darkness is in there but I think it was never explored because like you said she began kissing Damon’s/Salvatore ass and her purpose was to just prop Damon (fucking plec) 😩🙄.
Bonnie’s darkness was supposed to be explored in season 4 with Expression. At the time I remember the writers and actors talking about her getting a dark storyline and hyping it all up, and, as usual, that hype turned out to be false, but in any case I do feel like that’s where the show establishes she has a dark side. Her killing Kai didn’t feel that OOC to me because she’s very no nonsense and it reminded me of when she almost killed Elena (which I still wish she did, had the Salvatore’s not been there I’m very sure she would have succeeded). She doesn’t just decide to kill Elena, Elena had literally stepped on her last nerve with petty shit she did not have time for–she did not have time for Kai and his antics so she killed him eliminating the nonsense.
But back to her dark side, there’s a reason it was such an exciting potential plot in season 4 and that’s because she had every reason to go dark which is established after Damon turns her mom. When she sees Rebekah has him tied up she just leaves him there, he turned he mom and then expected her to be grateful that she didn’t just kill her. Everyone always expects her to “get over herself” and help them. There is so much repressed with Bonnie that the only real way to get it out is to explore her dark side, but show never does because a) that would give her agency and b) no one would have a leg to stand on they can’t paint her as the villain of the situation because she’d be right and especially in reference to the MFG who’s morals are lose at best.
Her being with Kai doesn’t really violate her morals because her reasons for them are personal. The reason she hates vampires is because her Grams dies because of it. The reason why she hates Silas is because he screwed with her head. The reason why she hates anything is because it directly effects her and while Kai does directly affects her isn’t the reason why she lose things. That’s why her forgiving Damon over Kai is so frustrating because she has lost a lot from Damon, but I do give her a lot of slack because all she needed was time to forgive which she was not given.
