Activate Ashnod's Altar by sacrificing Drowner of Hope, adding CC.
When Drowner of Hope dies, Nim Deathmantle triggers, causing you to pay 4 to return Drowner of Hope from your graveyard to the battlefield and attach Nim Deathmantle to it.
When Drowner of Hope enters, it triggers, creating two creature tokens.
Activate Ashnod's Altar by sacrificing a creature token, adding CC.