I know that traditionally in manga the student council has more power than the government. But in this school the council can just execute other students based on rules they themselves made up? Lol what?
I mean I can come up with a couple half-assed excuses to try and explain it.
1. For all we know Kalida could be a princess or something.
2. This is a fictional world inside of a fictional video game, I can see some writer creating this subplot for their game to cause conflict for the player to conquer with their love interest.
3. Kalida has like huge blackmail on every noble in the world and can do whatever she wants because she can protect herself with blackmail.
The real reason tho is definitely just because this is wildly entertaining because of how insane the plot just got.