Nice idea!
Chaos Chess (my Variant Idea)

you didn't show how the Demon moves
The demon is a Long Leaper that is restricted to Rook directions, the Long Leaper is a piece from Ultima Chess that moves like a Queen but after capturing something then it must move again in that same direction to a empty square or capture more pieces that way:
so there’s how the demon moves and captures:

The catapult should also have loads and be lke rifle chess piece.
I decided to make the catapult able to “throw” pieces behind it because it makes more sense if you think about it

But then it ends up up like the cannon .
It has to be dependent all times.I suggest that it should be given a weak base attack.

But then it ends up up like the cannon .
It has to be dependent all times.I suggest that it should be given a weak base attack.
I will think about it

Else the catapult is a extremely good and really unique idea . Finally something that is original . I am bored of pieces with just diffrent moves and capture.
This is a Variant idea created by myself, i took a lot of inspiration from Ultima Chess, it has a lot of pieces with special forms of capture, there’s the initial position:
Demon: a Long Leaper From Ultima Chess that is restricted to Rook directions
Other rules:
Stalemate: Stalemated player loses
Pawn Promotion: Pawns don’t promote to anything
Castling: there’s no casting
En passant: there’s no en passant
Pieces notation:
King: K
Antelope: A
Catapult: C
Crocodile: R
Clown: L
Demon: D
Giraffe: G
Furnace: F
Star: S
Pawn: P
Feel free to rate this variant idea, I really don’t know about pieces value, you can suggest values for the pieces if you want