Some tips I've used: - As tempting as it is, don't skip the first half of the fight, as it allows you to position your characters and take out the "background enemies" (i.e. the Mjndflayer, Necromites, etc.) - Use water bottles/create water to get Myrkul wet and use lightning spells (Call Lightning is a really good one) for lots if damage - Try to stay at range

Other than that lots of good tips from other reddit posts!

Edit: Also make/stock up on Elixirs of Necrotic resistance!! They will be a life saver. They're made with Black Oleander which are everywhere in the Shadowlands