History of All for One, One for All

'''All for One, One for All''' is the triumph for the Insurrection Prime encounter challenge in the Scourge of the Past raid (Black Armory), added in Season 5. The name is the Musketeers' motto: the whole fireteam must cooperate.

== How the challenge works ==

Three underground terminals each give a buff (symbols: square on the left, circle on top, triangle on the right).

All six players must receive each of the three buffs across the fight, rotating which buff each person gets.

Carry the buffs to the tank drop-off points (each takes two charges), which spawns a tank for the damage phase.

Fireteams usually split into two teams: one goes underground while the other handles the surface, then swap.

Repeat until three tanks have spawned, then kill the boss.

== Tips ==

• Do not abandon the damage phase after collecting buffs: the boss will end the encounter if minimum damage isn't dealt. Do enough damage but do not over-damage early, so the boss survives all three rotations.
• Use Checkpoints/encounter selection to retry only this fight.

Note: the sources I could open are community discussion rather than a full guide. A similarly named challenge may exist in other activities; this page covers the Scourge of the Past one.