Fire Staff kind of is the answer to all of Mistlands' trouble.
Massive AoE Damage and Knockback easily deals with Seeker and Tick Hordes out in the open and Dungeons alike, Hares can be instantly blasted with the hard to miss AoE before they can juke away, and Gjall's it easily takes down too with the massive damage as well as huge Burning DoT keeping them lit up and visible in the sky even through the fog - as well as taking no limited resource like Arrows or Bolts - and freeing up all your stamina for dodging and running from attacks, as Magic just consumes Eitr, meaning you are also never caught off guard with no stamina to attack after traversal, kiting and the like.
Combine it with Staff of Protection for a couple hundred HP Barrier with leveled Blood Magic so you can go triple Eitr Food (or double Eitr + one Stamina for traversal), and the game, including Mistlands and Gjall's, becomes a breeze.