Relic Axe of Helgni

When this relic enters the battlefield, if all other Helgni
Relics are on the battlefield under your control, Summon
"Helgni, Above Time" to the battlefield under your
control.

{u}{x}, Equip to target creature. Target creature gains
+X/+0 until the end of turn.

You can cast up to one instant or sorcery card per turn
from your graveyard. If a card is cast this way, exile it
after use.