And listen... You can hear them from far away long before you agro them. Just learn to play Mistland, it's a new biom and you need to adopt to it. You can not just play it like your are in the Meadows.
1. Listen
2. Have the wisp light
3. Listen
4. Move slowly so the light can clear the fog
5. Listen
6. Have proper food (180+ HP, 120+ stamina) and the Bonemass buff.
7. Listen
8. If you run away (which is a good thing to to in the beginning) put away your weapon and shield as it slows you down and uses up your stamina. And don't jump around like a CS-kid as useless jumping also kills your stamina.
9. The dwarfs are your friends, pull the mobs to their bases and they kill them for you. Just don't harm the dwarfs or their buildings.
10. The steep mountains and cliffs are your friends as seaker soldiers can not follow you there.
12. There is no need to climb the steep rocks as there is nothing up there. And if there is some dwarf post somewhere you can see the blue lights from far away.
13. Frostener (hammer) is your friend when it comes to fighting. The pure damage numbers may be worse than some black metal weapons but it freezes the enemy and slows it down so you can better hit it and maybe even hit them from behind.
14. Mistland creatures like to be hit from behind, deals double the damage if you hit them on their as s 🤪
15. Did I mention to listen into the fog.

Yes Mistland are hard and the terrain can kill you but that's part of the challenge, adopt to it or use mods to make it easier for you.