WHAT

He's assassin's guild master... if I'm not wrong, is been so long since last I read the novel.

He didn't know who the target was in the beginning. I remember that the guild just took on the commission and he didn't check until later but then he stopped and even killed the guy who commissioned it after finding out the target was Camila. Might differ a little from what I remember since it's been a while but this one I'm sure, he's innocent in this matter, just that his guild was involved, not him.

In the previous chapters when Camilla was still in the Fable empire and was in school, she helped out Lila who was being bullied by the student council president. She ruined the reputation of both SC prez and her father, who was a scumbag and a count. In revenge the scumbag count hired an assassination guild, Jainer’s guild, to kill Camilla since she was the reason both his family and business was ruined. Obvs the attempts failed, Jainer decided to cut his loses since both Sorphel Duchy and Arsen were attacking and killing every member of his guild. Jainer killed the count and gave his head to Duke Sorphel in exchange for them to stop them from attacking his guild.

He didn’t know about Camilla, just knew she was the target and he wasn’t involved in the attempts, he probably accepted the job. It wasn’t revealed until a bit later that she was technically his step-sister. If he knew than he probably wouldn’t have accepted, especially since the reveal of a sister never happened before and peeked his interest.