 If you liked
Itou-san
|
 ...then you might like
Heartless
|
Dark BL mangas that include a well established cult/secret society and their main characters trying to escape from them. Even in such despair they share the same underlying concept of trying to set their loved one free from all the shitty situations they're going through. I would dare say Itou-san is 1% more friendly while Heartless tends to show a good amount of insides flying around, but to be honest the two of them tackle some ruthless topics filled with either bittersweetness or pain. Or both!