Knight of the Last Breath

Knight of the Last Breath is Commander's natural habitat — seven mana is acceptable in a format with Sol Ring and Cultivate, and aristocrats or sacrifice loops give the death-trigger real legs. In competitive 60-card formats like Modern or Legacy, it never sees play; the rate is simply too slow for a format where games end on turn four. Pioneer is the same story: the token generation is fine in theory, but nothing in that format wants to spend seven mana on a 3/3 without an immediate board impact. Oathbreaker mirrors Commander's dynamics closely enough that the same shell evaluation applies — if you're running a sacrifice-themed signature spell, Knight of the Last Breath can pull weight.