So I was reading the UESP article on Ash spawn. I was wondering, what exactly are they weak to, if anything? I know they have a 75pt Fire Resistance. What about Lurkers and Seekers?

Ash spawn are weak to ice if using magic, or a good blade. Lurkers and Seekers are weak to fire, or a good blade. At least that has been what has happened for me in the magic department.

I didn't think Lurkers would be weak to fire. They seem so...fishy. XD That's something new to me. I guess I'll bring a couple fire and ice weapons along with me.

When you run into a seeker, if you stay focused on the "main" one, when that one goes down, the rest do also.

Looking at the Stats for Ash Spawn, they have no weakness. They are poison immune and fire resistant.