So inside of Thresh's lantern he has souls. Are these souls jealous of the outside world or the living people? Since they do not have their bodies anymore and are stuck inside a prison for eternity? Wouldn't they make them kinda evil now? I mean the souls can't be good after all they went through and they are probably furious.
I always said it.
is Senna (Lucians Wife) that has been corrupted by 
torturing her in his lantern.
On the subject of the souls in Thresh's lantern, you're forgetting that Thresh tortures them. These souls are no more than scared slaves that feel nothing but pain. I don't think they have time for being angry, they're too busy suffering and hoping for their misery to end.
