All other permanents on the battlefield (Deathrender attached to a creature you control).
If the creature with Deathrender attached is an artifact creature and/or is not a Dragon, you have a nonartifact Dragon creature card in your graveyard.
Steps
Activate Ashnod's Altar by sacrificing the creature with Deathrender attached, adding ({C} magic symbol) ({C} magic symbol) .
When the creature dies, Deathrender triggers, putting Bladewing from your hand onto the battlefield.
When Bladewing enters the battlefield, it and Cloudstone Curio trigger.
Resolve the Cloudstone Curio trigger, choosing to return nothing to your hand from the battlefield.
Resolve the Bladewing trigger, returning any nonartifact creature card from your graveyard to the battlefield.
When the creature enters the battlefield, Cloudstone Curio triggers, returning Bladewing from the battlefield to your hand.
Activate Deathrender's equip ability by paying ({2} magic symbol) , attaching it to the creature.