In Arcane Powers, the Arcane Sword epic destiny gives you the Sword's Vengeance daily power that basically lets you keep fighting in an untargetable state after you die. Even if you were fighting the craziest god ever, wouldn't this power essentially make you invincible and be able to kill it? I just don't see how your party can lose the encounter when you have this power.
Sword's Vengeance (24th level): Once per day. when you die, your sword fights on in your stead until the end of the encounter. Each round, the sword can move and make attacks as if you were still wielding it. but it cannot be the target of any attack. At the end of the encounter, after a short rest, the sword returns to your body, and if your body is still present, you return to life with 1 hit point. If your body is missing, you will need other magic to return to life.