Bandit: B&E

 is a challenge in Risk of Rain 2. It is completed as Bandit by killing the final boss with Lights Out.

Tips

 * This is pretty self-explanatory, though you'd have to be careful depending on the items you've acquired not to accidentally kill Mithrix from the effects of those items.
 * This includes and, as the damage from their effect occurs after the damage from Lights Out.