From multiversal + -ly.
multiversally (comparative more multiversally, superlative most multiversally)
- (rare, physics, science fiction, fantasy, cosmology) In a multiversal manner.
1980, TSR, Frank Mentzer, Dungeons & Dragons 1st Edition: The Immortal Storm Complete[1], Rainbow Communications, →ISBN, page 25:The mission is critical but need not be rushed. The storm has been brewing for several weeks, and will not reach multiversally devastating proportions for a few months.
2014, Dan Abnett, Rocket Raccoon and Groot: Steal the Galaxy!: An Original Novel of the Marvel Universe[2], Marvel Worldwide, →ISBN, page 148:I have no knowledge of any Project 616,” I say. "I can only conjecture. Let me think.. .'616' is the multiversally agreed designature of this Universe.”
2016, Linda Varsell Smith, Star Stuff: A Soul-Splinter Experiences the Cosmos[3], Rainbow Communications, →ISBN, page 25:Our answer: Well, duh! Multiversally, baby.