When a unit with 4 Might is played at Trifarian War Camp (which gives +1 Might), does it trigger Voli Legend's ability (which requires playing a unit with 5+ Might)?

Ruling: Yes, a 4 Might unit played at Trifarian War Camp will trigger Voli Legend's ability because "when I'm played" triggers check after the unit is already on the board, at which point the War Camp's continuous buff has already applied.

Sequence:

• The unit enters the board at Trifarian War Camp
• War Camp's continuous passive effect immediately applies, giving +1 Might
• "When played" triggers (like Voli Legend) check at this point and see the unit as 5 Might
• The trigger goes on the chain

Nuances:

• War Camp's passive effect is continuous and never goes on the chain - it always applies to units present at that battlefield
• Voli Legend only triggers when you play a unit that is Mighty at the time of checking (when it hits the board), not on all units with a check on resolution
• You cannot play a non-Mighty unit, then boost it in response to make Voli trigger - the trigger condition is checked when the unit enters play