So....character development for Rook Blonko.....
I came up with the idea that maybe he's been watching whatever the Ben 10 universe has as "The Godfather", or just mafia/mob movies in general. This would lead to some strange new ability to use smooth talk to benefit the Plumbers or catch some low level baddies...say Nyancy Chan or Fistina.
I went further with this and it evolved into Rook using criminal methods to control petty criminals while still being a "good guy", such as giving calm/passive aggressive threats to keep the petty criminals from doing anything to cause trouble. In a nutshell, Rook becomes a Don.
To make this more believable and in-character, Rook can know and understand how far his smooth talking can go. Sure it could keep petty thieves from stealing dangerous weaponry but he should know it wouldn't work on an alien who wants his best friend's head stuffed and mounted or just plain dead.
On a side note, for female criminals, Rook can just smooth talk them and arrest them when they let their guard down(in a nutshell again, be a troll).
So yeah.... I usually draw these ideas from thngs I read or watch.