Hafnar Ice-Fist was a Nord sorcerer and a member of Atmah's expedition to Labyrinthian, who was killed there with most of the others. His ghost can still be found there in various places where strong psychic impressions of past conversations and events were left behind.
Along with Atmah, Hafnar is one of the enthralled wizards that keep Morokei trapped in Labyrinthian. The Dragonborn can discover this by listening to the conversations repeated by the psychic impressions that are triggered as they travel through Labyrinthian during the quest The Staff of Magnus, which detail that Girduin, Elvali Veren and Takes-In-Light all die prior to the remaining mages who confront Morokei.
Savos: "Come on, we're finally here! Let's not waste any more time!"
Takes-In-Light: "Are we truly sure this is a good idea?"
Atmah: "We'll be back at the College before anyone even knows we're gone."
Girduin: "You would care about that, since you're the Arch-Mage's favorite!"
Savos: "Don't forget, this whole idea was Atmah's to begin with."
Hafnar: "Let's just get inside, see what's in there."
Elvali: "I can't believe we're doing this."
Savos: "Can you imagine the looks on their faces when we come back?"
Hafnar: "You keep talking like you're sure we'll find something useful in here."
Girduin: "Given the history of this place, it's more than likely there's still some amount of power here."
Savos: "Enchanted weapons, tomes of ancient knowledge, Shalidor's secrets themselves -- who knows what we could find!"
Takes-In-Light: "And what if... What if there are things guarding this place?"
Atmah: "Against six College-trained mages? I think we'll be fine."
Elvali: "We... we have to go back. We can't leave Girduin..."
Hafnar: "We barely made it out alive, and you want to go back in?"
Atmah: "It's too late. There isn't enough of him left to go back in after."
Takes-In-Light: "Gods, what have we done?"
Savos: "We can't go back. Might as well go forward. We can still do this."
Atmah: "Savos is right. We can make it if we just stay alert."
Savos: "Come on, we can't stop now. We have to keep moving!"
Atmah: "Where's Elvali? She was right behind me."
Hafnar: "Dead. Something grabbed her from behind. Gone before I could do anything."
Takes-In-Light: "This is insanity. We never should've come here."
Atmah: "You're right. This is all my fault. Should we turn around, head back?"
Hafnar: "I don't think going back is a good idea."
Savos: "Going back would be the end of all of us. We keep pushing forward, and we'll make it. We will!"
Atmah: "Come on, you can make it. Let's go."
Atmah: "We shouldn't have left her there to die!"
Savos: "What else could we do? Stay there and die with her? She refused to go on, we didn't have a choice!"
Hafnar: "This is it, you know. Through this door. Can you feel it?"
Atmah: "We're not going to make it, are we?"
Hafnar: "We stay together, no matter what. Agreed?"
Atmah: "I'll be right with you."
Savos: "Agreed. We all stay together."