When Su-Chi dies, it triggers, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Resolve the Altar of Dementia ability, causing target player to mill cards equal to Su-Chi's power.
Activate Soldevi Digger by paying ({2} magic symbol) , putting Su-Chi on the bottom of your library from your graveyard.
Activate Grenzo by paying ({2} magic symbol) , putting Su-Chi into your graveyard from the bottom of your library, and then putting it onto the battlefield.