Hello

Hello is a transparent, passive NPC that spawns in the Castle dream, as well as the old version of Ocean Lab. It is completely and utterly harmless, as it's sole purpose is to move at extreme speeds towards the nearest passive NPC. They are able to wear hats, and can be net with the Shiny Net as well. They will often respawn in the dream due to moving so fast they clip out of the net dimension, or bouncing off of something.

Hell
Hell is a variation of Hello, colored brightly red and with their head detached at the point where they spawn. The only difference is that Hell tend to jump more, and have an incredibly high JumpPower. They tend to move more towards other Hells.

He'll
He'll is another variation of Hello, colored grey as if ghost-like. Instead of moving towards other NPCs, they instead spawn stacked ontop of eachother, in the fact that they are welded to eachother and cannot be seperated. They simply wander around, at a normal walkspeed and jumpheight. It may be that the name He'll is a metaphor for something, perhaps Josafa doing something. If combined with Hell, it may be telling us that Josafa plans to send the protagonist to hell?