Everything that happened during the events of Avengers #1? It's all the fault of the Avengers from 1,000,000 BC. That's what Marvel's Free Comic Book Day offering has to say.
In Marvel Legacy #1 back in September, a prehistoric version of the Avengers made their debut. This team included counterparts to the modern day team, including a young Odin, the first Iron Fist, a Black Panther, a Hulk-like Starbrand, the Phoenix, and a Ghost Rider who rode a woolly mammoth. These heroes came together to fight off the Fallen Celestial, but what came after doomed the Earth to a terrible attack one million years later.
This is a story by Jason Aaron and Sara Pichelli that fills in between the panels of Avengers #1. It's the #0 issue you didn't see coming, but it also propels us into the future of Aaron and Ed McGuinness' run on the title.
The Confession One Million Years in the Making
The issue starts off with something of a confession. Black Panther has never met Odin, the god king of Asgard before, and yet Odin knows him. T'Challa's ancestor once fought at Odin's side, so the Asgardian feels something of a kinship with the king of Wakanda. Maybe this is why he asks Black Panther to meet with him in secret among the ruins of Asgard. This is where he confides in "an old friend" about the mistake the BC Avengers made all those years ago.
It would seem that simply killing the Fallen Celestial (if they could even accomplish that) was something of a mistake on their part. In the heat of the moment, this cosmic being may have seemed like a force of destruction, but it was also clear that the Celestial was sick. Perhaps they could have helped it instead of hurt it. The BC Avengers, not knowing what else to do, buried the gigantic lifeform and tried to forget about it. Unfortunately, secrets can only be hidden for so long, and even after a million years, the truth has to come out.
The Black Panther of 1,00,000 BC warns the group that by killing this sick Celestial now, they may have made the world a target. "I fear what next will come from the sky. This time not mindless. But sick only with vengeance." And as the first Black Panther foretold, some unknowable cosmic force has come to Earth in the present day, and though we don't yet know how, it's clear that the two events are connected. Revenge has arrived.
The Fate of the Fallen Celestial Revealed
Remember the Fallen Celestial? Back in Marvel Legacy #1, Loki discovered the cosmic being still living under ground in modern day. It was calling out for the Final Host then, who just now arrived in Avengers #1. Loki seems to have aligned himself with the Celestial for some unknown reason, but as the God of Mischief does he really need to explain why he's messing with his father's legacy?
It seems that Loki was the one who helped summon the Dark Celestials to Earth, and now he has taken the Fallen Celestial with him. Just like old times, it would appear that the mischief of Loki has brought the Avengers together again. At this point it seems like fate, that when he starts trouble, the Earth's Mightiest Heroes will be there to stop him. However, Loki is going to be packing some serious reinforcements this time around.
The reason the Fallen Celestial is no longer underground for Black Panther to find in Avengers #1 is because Loki had already brought it with him to meet with Odin. It was their attack on him that prompted Odin to seek out T'Challa and request something of the hero. The god knows his son has caused more trouble than he should be allowed to get away with. However, even after everything, Odin doesn't have the heart to do what must be done. He asks that the Black Panther finally kills his son once and for all.