Master of Diversion

In Commander, Master of Diversion is too fragile and too small — the effect is real but three mana for a 2/2 that taps one creature per attack cycle doesn't keep pace with the threats at a four-player table. Pauper is the format where it's most plausible, particularly in white weenie or Boros go-wide shells that can attack in numbers and need incremental evasion to close games. In Modern, Pioneer, Legacy, and Vintage, the card is far too slow and underpowered relative to the threats those formats present — it's legal but not viable. Oathbreaker follows the same logic as Commander: the effect is serviceable, but the rate loses to nearly every alternative.