Thor and the Eternals

Thor and the Eternals: The Celestials Saga (1979-1980/This collection 2020): written by Roy Thomas, Mark Gruenwald, and Ralph Macchio; illustrated by Keith Pollard, Chic Stone, John Buscema, and Gene Day; adapting portions of Richard Wagner's RING CYCLE (seriously): 

Say what you will about longtime comic-book writer Roy Thomas, but he really likes Norse mythology and Wagner's RING CYCLE. So much so that he shoehorns a really wonky take on the former and an even wonkier shoehorning of the latter into this lengthy attempt to fit Jack Kirby's Eternals into mainstream Marvel continuity.

As it wasn't enough to just figure out how the Eternals could possibly fit into Marvel's already overstuffed pantheons of Norse, Greek, and pretty much every other god on record with the exception of the Christian ones, Roy said, no, I'm also going to offer a new expanded origin for the Norse gods seen in THOR. And I'm going to adapt the RING CYCLE. And the RING CYCLE will explain mysteries of Thor's origins that no one realized were mysteries before. 

And I'll have a sizeable portion of this story narrated by the sentient, giant floating eyeball that Odin sacrificed for knowledge back when the eye was neither sentient nor floating nor giant. The eyeball will tell this story to the titular hero of this saga, Thor, who will be almost as baffled as the readers will be. 

And then Roy left Marvel before the story was over, leaving Mark Gruenwald and Ralph Macchio to figure out how to end the whole thing, though I assume Roy may have left notes or something,

It's far and away the craziest cosmic saga of Marvel's Bronze Age, ably illustrated by John Buscema and the always under-rated Keith Pollard. Roy would go on to retell the Norse Ragnarok with DC's Justice Society of America chipping in to help the Norse gods. Then he and artist Gil Kane would adapt the RING CYCLE in the early 1990's, this time without added superheroes. Because it don't mean a thing if it ain't got that Ring... of the Nibelung! Recommended.