The following contains spoilers for Avengers 1,000,000 B.C. #1, available now from Marvel Comics.
The story of the first Avengers is heartbreaking at best. Each individual member of the team is fraught with tragedy and heartache despite the incredible legacies they left behind. Unfortunately, there is one original hero whose legacy has always been just as painful as his untimely demise. As has recently been revealed, it was the death of the very first Black Panther which set the precedent for Wakanda's oldest rule in the worst way possible.
After facing off against yet another impossible threat, the heroes of Avengers 1,000,000 B.C. #1 (by Jason Aaron, Kev Walker, Dean White, and VC's Cory Petit) are left to ensure that their world endures the trials that still await it. Not all the Stone Age Avengers are imbued with powers like the Starbrand or Phoenix Force, and the eventuality that is death catches up to the Black Panther, Mosi, before any others. In the somber silence following Mosi's demise, the Phoenix takes it upon herself to reach out to her former teammate's tribe, only for them to officially rebuke her and the rest of the world entirely.
Despite the sincerity of Firehair's words, the other members of the Panther Tribe want nothing to do with the Avengers who they see as interlopers at best, and harbingers of doom at worst. This isn't all that surprising considering it was the Avengers' battle against King Laufey and Hyve that led to the Black Panther's demise, yet he had already dedicated his life to safeguarding the world long before that. Even still, the loss of their leader is more than reason enough for the Panther Tribe to venture forth into the night on their own in the hopes that everyone else will simply forget they ever existed.
While this is itself a devastating scene to see play out, it is also the beginning of the isolation that would go on to define Wakanda for millennia. When the nation first appeared in the pages of 1966's Fantastic Four #52 (by Stan Lee and Jack Kirby), it was a barely known country full of intrigue and mystery. This was largely due to Wakanda having remained hidden for so long, all in a bid to protect its precious supply of vibranium. At least, that was the popular belief at the time, but Mosi's death shows that there was always so much more to the decision to hide Wakanda.
From the beginning, outside influences stood in the way of Wakanda's prosperity. For the earliest members of the Panther Tribe, Mosi's death was the result of his dealings with outsiders, no matter how many times he saved the world from infernal or Celestial threats alongside them. As such, turning their backs on the rest of the world was the easiest choice for them to make.
In the thousands of years since Mosi's death, Wakanda has risen to prominence as a global superpower solely on the back of its own advancements. It has also managed to splinter itself into multiple factions, some of which have chosen to isolate themselves from the rest of Wakanda up until only very recently. This may not be symptomatic of the country's more generalized fears, yet there is no question that the zealous adherence to the tradition which divided the old Wakanda absolutely is. As harrowing as the secret history behind those fears might be, everything that followed for Wakanda is a testament to its legitimacy.