Enter Abbadon, an ultimate Darkness summon from my post-apocalyptic world that I can't really describe well :I

The young boy was able to make a contract with Abbadon, but unable to control him, as many before him. The lucky child did manage to survive, however, and thus remains the demon's main method of transportation.

I think my idea of summoning spirits is akin to what was in Descendants of Darkness, where some are just summon summons, and some are parasitic(like this) and others do other things, but they are separate entities.

Something.

LOOK A BAT DRAGON MONSTER