The undead monster with the white, wild hair is actually a Banshee...it's far worse than any Wight we'd ever find.
The green spiky thing is a Needle Nettle, a destructive and mischievious fey creature that live in the woods and like to give nice tight hugs. Creatures do not usually like being hugged by these imps for obvious reasons.
The posessed toy is a "Divagating Doll" which isn't anything more than an animated ojbect which happens to be a doll.
Would this game be free? How would you deal with copyright otherwise?
What's copyrighted? All the monsters here are either homebrew or public domain. There are only a few monsters D&D have copyrights on and they aren't in the game. The game also doesn't use any of D&D's game mechanics.
Hmm, good point, I imagine you couldn't use Githyanki but you could use Pit Fiend. Monsters in your world are sort of interesting because they are almost like body doubles of the standard D&D creatures, the same except due to the context of your world they are often very different, AKA your Devils vs. Planescape Devils