Grym Fighting Tips
The fight is fine, difficult, but by grym forge the standard mechanics required to deal with this boss should be known by now (levels 4-5). You can examine the bosses weaknesses with a right click and swiftly intuit the lava/hammer/lever option.
You can perceive its active debuffs under its name tag. All characters can dash. If you have mage hands they can pull the levers. You can also shoot the levers. The boss itself is as mechanically simple as they come. It attacks whatever hit it last. There is a popup prompt that even says so when it’s target shifts. If you forget who it targeted, your party portraits will say who is targeted.
The boss can be frustrating on tactician difficulty in that the health pool demands 4 hits with the forge hammer and a little bit of bashing on the side. I recommend the spell “shatter” and Pepe’s Chosen, the hammer toad Lae’zel. If on tactician you can not spam the hammer, the boss must step from lava to forge plate and back to lava to receive the vital debuff. If you are on tactician and do not have any blunt weapons and having a hard time… you’ve made a mistake and must embrace the suck :(. Spirit weapon maul WILL be known by Shadowheart. It is also chosen by Pepe, say his name when you pray.
Game difficulty options are available in the options menu.
The rewards for beating this boss are endgame level… if you select the armour or shield.
Grym is always immune to most elemental damage and highly resistant to physical damage. While he’s standing in Lava, and for two rounds after he leaves the lava, his physical resistances drop and his Bludgeoning resistance in particular flips into a bludgeoning weakness. Thus anything that deals bludgeoning damage is what you want to use to fight him, even if it’s just a quarterstaff or one of the Forge’s molds as an improvised weapon.
Personally, using the forge’s hammer never crossed my mind, and to date I’ve never managed to position him correctly to be hit by it. Instead what I do is take Lae’zel and Karlach into that fight, have them chug speed potions, and give them whatever random bludgeons I can find scattered around. Greatclubs and quarterstaves are incredibly common, and the treasure horde behind Ragzlin in the Goblin camp has a quality hammer for the fight if you picked it up earlier. The other two can be whoever you like, preferably someone that can buff or debuff the others because damage is a waste of an action unless you’re using a club.