Once Summon: Primal Odin deals combat damage to a player and the ability granted by Summon: Primal Odin's second chapter ability triggers, it doesn't matter what happens to Summon: Primal Odin. When that ability resolves, the player who was dealt combat damage this way loses the game even if Summon: Primal Odin isn't on the battlefield anymore or is controlled by another player.