Tetrarchy
In this variant four pieces in the starting position are replaced with Tetrarchs. Tetrarchs flip between the moveset of a King or a Queen when moved. All the rules of Chess apply except that: (1) there is no castling, (2) stalemate is a loss for the stalemated player, (3) a player wins if one of their Pawns reaches the final rank ("Pawn-mate"), and (4) a player loses if no Tetrarchs remain on the King side. Checks do not apply to the Tetrarchs.