Under these rules even King vs King would be a win for one of the players. Would that really be what you want? It sounds a bit arbitrary. You might as well flip a coin before the match to decide who wins in case of what otherwise would be a draw.
Expanded Chess

I think it might be interesting. It's not really an important part of the game to me. I was trying to think of a simple way to preclude draws, just for the sake of doing it The difference with flipping a coin is that the players can't influence a coin flip, but they can try to be the last one to capture. King vs King shouldn't happen very often in this game anyway due to the promotion rules.

If you have any ideas for names please tell me. I can't think of good ones; but I do think 'Osprey' is good and matches the movement of the piece somehow.

Visit musketeer chess website and look for board painter in tools

I have an idea, how about adding a Bison (Camel and Zebra combined) between the Osprey and Lion to complement the Knight, and the Hawk (from Musketeer Chess), a piece that jumps exactly two or three spaces in a straight line, positioned in the corner squares to complement the Queen (Since Duchess (Hawk + Mann (Non-royal King)) is a bit too powerful to appear in pairs in a 10*10 board)? The pawns will be able to promote to any of these two pieces on the 9th rank (Since these two pieces are about Rook strength and both are major pieces)

I have an idea, how about adding a Bison (Camel and Zebra combined) between the Osprey and Lion to complement the Knight, and the Hawk (from Musketeer Chess), a piece that jumps exactly two or three spaces in a straight line, positioned in the corner squares to complement the Queen (Since Duchess (Hawk + Mann (Non-royal King)) is a bit too powerful to appear in pairs in a 10*10 board)? The pawns will be able to promote to any of these two pieces on the 9th rank (Since these two pieces are about Rook strength and both are major pieces)
Nice idea
This is a simple expansion of chess to a 10x10 board. The two additional pieces complement the rook and bishop.
This is the initial setup.
The Lion moves my first taking a single diagonal step and then sliding outwards as a rook.
The Osprey moves is to the Lion what the Bishop is to the Rook. It's move is a 45° rotation of the Lion's. The Osprey moves by leaping to the second square on the same rank or file, and then sliding outwards as a Bishop.
Pawns have the option of an initial double step, and may capture en passant.
A pawn may be promoted on the 8th, 9th, or 10th rank. On the 8th rank, a pawn may only be promoted to a Knight, Bishop, or Osprey. On the 9th rank it may only be promoted to a Rook or Lion. If a pawn reaches the 10th rank, it must be promoted to a Queen.
Checkmate and Stalemate are wins for the player delivering mate. If a sequence of 50 moves by each player occurs with neither player making any captures or pawn moves, the game is over and the player who made the last move wins.
In a previous version of this game, I had another piece to complement the knight, that made a 3,2 leap. I removed it because I felt it made the opening too delicate.
It might be better to have the Ospreys start directly behind the King and Queen.