What are those lines?

Have you ever seen them on the ground, or are they appear in the air?

Like a defense maybe?

Had that scenario somehow occurred (it would take Kirby being on far better terms with Lee at the time and never moving to California, I think) and Thor was replaced in the Marvel Universe by Orion and his compatriots, the likes of Thomas, Englehart, and others would never let it stand. Thor, Odin, and all of Asgard would HAVE to have been brought back at some point, thoroughly mixing and muddling both concepts, perhaps beyond recognition.

Darkseid, the major player in the Fourth World saga, would not stand out as much at Marvel and could have receded into the background as a better-looking Kurrgo, Master of Planet X. Then again, no one at Marvel would have felt the need to create their own "New Gods" cosmic-style storylines and there would likely be no Thanos. Darkseid might have taken the place of Thanos.

Also, if the various criss-crosses across company boundaries hadn't taken place as they had, Kirby would likely not have come up with the Eternals as a Marvel comeback idea, meaning no Celestials, unless he conceived of them in some other context. Would his fascination with Mayan iconography and "Chariot of the Gods" still may have manifested itself in the Eternals? 

Wherever he worked, Kirby was a non-stop font of creative concepts, so who's to say what would have been developed where if he'd stayed with Marvel? Everything ultimately comes down to the stories told with the characters. If Darkseid was prominent in well-written, exciting Marvel stories, he'd have done well there.