Stalwart Valkyrie
Creature — Angel Warrior
You may pay 
and exile a creature card from your graveyard rather than pay this spell's mana cost.
Flying
"Only the worthy may pass."
3/2
Illustrated by
Jumpstart 2022#249CommonEnglishLegality
Rulings
Feb 5, 2021
Casting Stalwart Valkyrie for its alternative cost doesn’t change when you can cast it.
Feb 5, 2021
Once you announce that you’re casting Stalwart Valkyrie using its alternative cost, no player may take other actions until the spell’s been paid for. Notably, players can’t try to remove creature cards from your graveyard to stop you from casting the spell.
Feb 5, 2021
Stalwart Valkyrie has converted mana cost 4, no matter what you actually paid to cast it.