"I won't pollute my blade with your blood, demon. You'll die by your own axe!"

Cleaving Reaper

Flying, trample
Pay 3 life: Return this card from your graveyard to your hand. Activate only if you had an Angel or Berserker enter the battlefield under your control this turn.

Kaldheim Promos

Kaldheim

The Angel or Berserker doesn't have to still be under your control in order to activate Cleaving Reaper's ability. Additionally, the Angel or Berserker could have entered the battlefield under your control at any point in the turn, even before Cleaving Reaper was put into the graveyard.