Middle English, "killer, agent of death, death," going back to Old English bana "killer, agent of death," going back to Germanic *banan- (whence also Old Frisian bana, bona "killer," Old High German bano "killer, murderer," Old Norse bani "murderer, violent death"), of uncertain origin
Note:
Another Germanic derivative from the same base is represented by Old English benn (feminine strong noun) "wound, sore," Old Saxon beniwunda, Old Norse ben "wound," Gothic banja "blow, wound." Attempts have been made to derive the etymon from Indo-European *gwhen- "strike, kill" (see defend), but the general view is that initial *gwh could not yield b in Germanic.
