Nia, One With the Sea

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Nia, One With the Sea deals combat
damage to a player, create a Gold token. (A Gold
token is an artifact with "Sacrifice this artifact: Add
one mana of any color to your mana pool.")
Twin sister (You can have two commanders if both
have twin sister.)