This tale is pretty important because someone other than Thor wields Mjolnir.
Just kidding. I mean, a guy on an alternate timeline (in the future) named Dargo Ktor does pick up Thor’s hammer, but this is not important. It’s a done-in-one. He becomes Thor for an issue when Loki attacks a city, Thor’s hammer is sitting in a stone somewhere waiting for someone worthy, and Mr. Ktor shows up.
Not sure if this is canon, but it was a solid fill-in story. (Not a fill in actually because it’s by the regular creative team, but content-wise it’s filler.)
Djargo will return.