If you play Sett (a 4 power unit that buffs itself when played) while Volibear is your Legend (which triggers when you play a Mighty/5+ power unit), does Volibear's ability trigger?

Ruling: No, Volibear's ability does not trigger when you play Sett. Sett enters as a 4 power unit, and even though both abilities would trigger at the same time, Volibear's trigger condition ("play a mighty unit") is not met at the trigger timing, so it never gets finalized onto the chain.

Sequence:

• Sett is played as a 4 power unit
• Both Sett's "When I'm played" and Volibear's "When you play a mighty unit" would trigger simultaneously
• Volibear's condition is checked at trigger timing and is not met (Sett is only 4 power)
• Only Sett's ability goes on the chain
• Sett's ability resolves and he becomes 5 power (but too late for Volibear)

Nuances:

• The words following "play" until the comma in Volibear's text are part of the trigger condition, not the effect
• A unit like Draven that enters with stats already at 5+ power would trigger Volibear