为 Urza, Lord Protector 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！
Artifact, instant, and sorcery spells you cast cost less to cast.
: If you both own and control Urza, Lord Protector and an artifact named The Mightstone and Weakstone, exile them, then meld them into Urza, Planeswalker. Activate only as a sorcery.
