so,I kinda worked a Lil bit bout dis,and I made a chess variant in which there is a 7x7 board,but all are pawns and a king hiding at da back of dem in a square labelled as X⁰ and X* for black and white respectively.
each pawn promotes into a knight—>bishop—>rook—>Queen and lastly,empress,which moves like a queen+knight.
VARIANT NAME——TETRACHESS