ウルフィーの銀心 (Wolfir Silverheart) (ja)
Creature - Wolf Warrior | Power/Toughness: 4 / 4 (CMC 5)
Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Wolfir Silverheart is paired with another creature, each of those creatures gets +4/+4.