At the start of the show, Shigaraki shows to be malevolent and twisted, not caring for anyone. His character develops clearly to "I'm going to kill anyone I don't like" to "I'm going to kill anyone who threatens me OR the league of villains". He treats the League as equals eventually, separating his plans from their own plans. As long as Shigaraki does what AFO wants, AFO is happy. He doesn't care what Shigaraki does outside of his plans. He shows respect to many of the League.