Wildfrost

This can only be done with Shadowmancer tribe.
This tribe contains shade cards, aka summons.

Pick up any kill ally cards (the 'Bonescraper' that lets you "sacrifice" an enemy doesn't seem to work for this).
Either stall until you kill five different summons, or you can use the companion card "Chikichi". It's a black chicken with a mask on.

This is a default companion you can find that respawns as a different card when sacrificed and switches back when sacrificed again.