In our campaign, we have a ranger, wizard (me), rogue, and a paladin. After a long trip through the underdark, asking a lot of people a lot of questions, and finally figuring out how to summon Demigorgon to a specific city so we could ambush him, this is what went down.
*2 hours of desperately clinging on to life as a level 11 party against Demigorgon*
Paladin *lands killing hit*
*city is in ruins*
Paladin: it’s ok everyone, he’s dead now *casts zone of truth on self* I killed him *dispells zone of truth*
*whole city showers him in gold and no one believed we helped*