Professor Onyx offers a planeswalker commander that leans into spell-heavy black control and lifedrain strategies. Her Magecraft ability rewards chaining multiple spells in a turn, which lines up well with common black draw and removal suites. Online decklists often pair her with combo pieces that exploit repeated life-loss triggers or infinite spell loops. Fans of villains, spell-slinger gameplay, and planeswalker commanders gravitate to Onyx as a stylish centerpiece for mono-black control.