My group just played against him yesterday and won, but it was pretty close. We played with the base, innsmouth, dunwich, the black goat and dark pharaoh expansions. Total of 4 players: the handyman, redeemed cultist, the violinist, and the professor. Myself (cultist) and handyman were blessed, and he still had his shotgun. I was pretty decked out with spells, and some unique items. The main reason we won was because of the violinist, she had some unreasonably large number of clue tokens due to hunting them all game and getting more when gates opened. When we fought him it wasn't too bad, handyman was first and knocked nearly 1/2 his counters off, but was devoured by the end of the round, then professor was devoured next round, and we beat him. He is very hard, I'd recommend having someone who is very good at getting clue tokens or has high mobility to do so and keeping shotguns. If you see him coming, make sure to get blessed, very useful. He is a very fun Ancient One to fight though.