In this issue, Thena of the Eternals is sent by Zuras to confront the Deviant Zakka, who is behind the sudden appearances of various creatures from the past into human cities. Thena takes along Karkas and the Reject, the recently rescued Deviant mutates from the regular series. Thena uses her powers to disguise Karkas and they're off. Thena and the Reject quickly encounter Jack the Ripper pulled forward in time, and stop him from killing before he vanishes. Meanwhile, Karkas is attacked by Atilla the Hun and one of his men, forcing him to reveal his true appearance.
He defeats them but terrifies everyone else, yet he still turns down Zakka's offer to join him, just as Thena and the Reject return. Tracking down Zakka, they face a final battle with Tutanix, an ancient Deviant mutate brought forward in time who first turns on Zakka and then battles Karkas and the Reject.
As you can see, Kirby's just tossing out concepts all over the place in this one, with a full 34-pages (then considered double size) to work with. It's a fun story, although it does point up how much wound up unexplored in THE ETERNALS, even with 19 issues and this annual. I'm sure Kirby could have done a lot more with Karkas in particular, but I think this is the only time he appeared outside of his introductory story.
Mike Royer inks the story, Frank Giacoia inks the cover.