I am pretty sure this has to do with the upcoming SHIELD series by Hickman. Has a similar Vitruvian Man/Galactus design. Some quick other points. Silver Surfer is currently a Galactus herald. Galactus has two as of now.Siege will be the last big Marvel cross title wide event for a while. (Siege will be involving New Angers, Dark Avengers, Mighty Avengers, Thor, Thunderbolts, New Mutants, Thunderbolts etc)War of Hulks/Fall of Hulks, Second Coming, etc all those will be restricted to their own corners of Marvel. Hulk books, X-Men books.

My guess on this is I think it pertains to sealing the FAULT & the threats that loom! The Realm of Kings arc looks like that will wrap up in March for all relevant titles involved so this would be a good continuation! I am guessing those are The time & space gems or the reality gem, & somehow they are tryin to seal the rift in space/time & Galactus somehow fits into this happening, with him being so unique that he is from the previous universe & has been in the current MU since the beginning! The fault is a threat to everyone so maybe someone has devised a permanent solution!