Nim Deathmantle attached to any creature you control except the creature with One with the Kami attached.
Steps
Activate Ashnod's Altar by sacrificing the creature with Nim Deathmantle attached, adding ({C} magic symbol) ({C} magic symbol) .
The creature dies, triggering Nim Deathmantle and One with the Kami.
Resolve the One with the Kami trigger, creating at least two 1/1 Spirit creature tokens.
Activate Ashnod's Altar by sacrificing a Spirit token, adding ({C} magic symbol) ({C} magic symbol) .
Resolve the Nim Deathmantle trigger from step 2, causing you to pay ({4} magic symbol) to return the creature from your graveyard to the battlefield, and attach Nim Deathmantle to it.