Legion is a legendary major card out of the New mechanic pool. Spirit Host marches 6 wisps for 10 s at 85% damage.

You can take it once · it only turns up when your Ultimate ability can actually use it · it can be offered for 0 of the 34 abilities.

Only one card can reshape that ability this way — this one, or Titan Host and Martyr Host. Take one and the rest are gone for the run.