[ BSC: Altaïr is a relatively young master airbender, and has recently become leader of a faction in the Southern Air Temple who have dismissed pacifism in the face of impending genocide. They've already fought off several raids by the Fire Nation using trickery and traps to force the armies back down the mountains, and in the uneasy lull before the next attack Altaïr is in search in knowledge that might help in the war.
Alternatively, catch him earlier when he was a little shit banished and sent on pilgrimage for killing a non-bender civilian at the start of the conflict, or later, when he's an aging sage travelling to Wan Shi Tong's spirit library after the destruction of the Air Temples. ]
Altaïr Ibn-La'Ahad | Assassin's Creed
Alternatively, catch him earlier when he was a little shit banished and sent on pilgrimage for killing a non-bender civilian at the start of the conflict, or later, when he's an aging sage travelling to Wan Shi Tong's spirit library after the destruction of the Air Temples. ]