Earth-276 was a world never visited by residents of the prime universes that survived through the final days of the Crisis on Infinite Earths, and yet it was the mirror image of one of these parallel planets known as Earth-S, which had been home to the Marvel Family. It's prime protector also once visited another prime universe in Earth-One.
Captain Thunder aka Willie Fawcett was the counterpart of Billy "Captain Marvel" Batson from Earth-S. Willie had been born on Earth-276 and came upon the acquaintance of Merokee, who like his own counterpart Shazam had imbued a lad with superhuman abilities. The Monster League of Evil had a long running enmity towards Thunder as had the Monster Society of Evil with Marvel, although in the former's case this pitched battled spilled out through some 1,953 dimension. Eventually, the Captain captured the League, leaving them in inter-dimensional Limbo existing between universes, however the League's leader used his mental abilities to warp the mind of Thunder. This led the caped crusader to erroneously venture to Earth-One instead of his home world, whereupon as young Willie happens upon both criminals and the costumed crimefighter, Superman.
However, when Fawcett transformed to Thunder, the Captain's suddenly evil disposition turned him into an adversary of Superman, and the two battled on a couple occasions, In between these encounters, Willie reverted to his childhood self and sought out reporter Clark Kent in hopes of the journalist helping to lead the teen to Superman. Together, they ascertained that Captain Thunder was acting against his true benevolent nature, and so Superman tricked his rival into utilizing his inherent wisdom to revert the Captain to his once righteous demeanor once more.
At that point, Captain Thunder calculated the means to travel back to his native Earth-276, at which point he disappeared from Earth-One's reality nevermore to return. Similar confrontations occurred between a mentally controlled Captain Marvel, who temporarily resided upon Earth-Two and battled that world's Superman, and decades later a similar occasion when he battled this same Superman who previously dueled with Thunder years previous. As to whether Captains Marvel and Thunder, Shazam and Merokee, or the Society and League of Monsters ever encountered one another is unknown, although given that Marvel and his Family where in suspended animation during the period when Thunder was traversing various dimensions before irrevocably returning to his Earth, it is unlikely.
As for Thunder's cosmic twin Captain Marvel, and later tale wherein Mister Mxyzptlk swapped the powers and costumes of Marvel and Superman, in a scheme wherein the imp was working alongside Mister Mind and King Kull to defeat the pair. This encounter solidified that Captain Marval, and by extension Captain Thunder their worlds' respective Supermen, even though neither originated on Krypton as has Kal-El and Kal-L. At the end of this crooked caper, wherein Mxyzptlk became disenchanted with the bloodthirsty demeanor of Mind and Kull, he returned to his 5th dimensional home after reversing the condition of Earth-One and Earth-S' mightiest men that restored them to normal.