为 Boromir, Warden of the Tower 寻找最佳的标准套牌，包括其胜率、热度，以及该牌在万智牌：竞技场中的合法赛制！
Vigilance
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.
Sacrifice Boromir: Creatures you control gain indestructible until end of turn. The Ring tempts you.
