Of all the forgotten heroes of both the DC and Marvel Universes, few oversights are as egregious as Access. In the mid-90s, multiple crossovers between DC Comics and Marvel Comics were published. These were the titles DC versus Marvel, DC/Marvel All-Access Unlimited Access and various one-shot team-ups between specific characters. In the span of a few years, the two companies created a series of fights and team-ups between their iconic heroes, accompanied by the characters literally merging into an amalgamation of DC and Marvel's universes.
At the center of it all was Axel Asher, better known as Access. Introduced in Ron Marz, Peter David, Dan Jurgens and Claudio Castellini's DC versus Marvel #1, this individual had the ability to travel between universes, specifically, the DC and Marvel Universes. Being aware of the two Brothers -- cosmic entities representative of the DC and Marvel Universes -- Access's job was to keep the universes separated. Since the complexities of corporate publishing have kept DC and Marvel from crossing over for well over a decade, Access has led a quiet life since he became the unlikely linchpin in one of comics' biggest crossovers.
How Axel Asher Saved the Multiverse
At the start of DC versus Marvel, Axel Asher was unable to stop the two Brothers from pitting their universes against each other, but he found a way to break up the fight after the two universes merged together. Asher gained his abilities after encountering an old man holding a box. The old man claimed to be one of a long line of individuals known as Access, tasked with keeping the multiverse apart.
Again, Access didn't stop the fight from ever happening, especially as the Two Brothers pitted their worlds together. However, the continued fighting threatened to eradicate both universes, forcing the Living Tribunal and the Spectre into merging the two realities into one Amalgam Universe, if only to pause the fight for awhile. This is where Access made his move.
When the two universes began to merge into one, Access found Captain America and Batman, who each possessed a shard of their original universes within their hearts, and convinced them to help break up the brothers' war with one another. This managed to end the conflict and save the two realities from being annihilated.
How Access Brought the X-Men and Justice League Together
However, this was far from the only time Access's powers became necessary. Ron Marz, Jackson Guice and Joe Rubenstein's follow-up DC/Marvel: All Access saw Dr. Strangefate -- the fusion of Doctor Strange and Doctor Fate -- try to recreate the Amalgam Universe once again. Their universal hijinks led to Venom nearly killing Superman, Jubilee and Timothy Drake getting together and the X-Men coming in conflict with the Justice League. However, Access and the assorted heroes helped prevent this from occurring.
Later on, in Karl Kesel and Pat Olliffe's Unlimited Access, Access learned that the old man who gave him his abilities in the first place wasn't some prior person with the Access powers, but rather just an old, alternate future version of himself, corrupted by Darkseid's destructive influence. To defeat Darkseid, however, Access allowed the Amalgam Universe to be created, merging with his evil half, dominating it, and allowing the heroes to join together to defeat Darkseid before he could enact his vile machinations.
What Happened to Access After Marvel vs DC?
The DC and Marvel Universes would continue to crossover after Unlimited Access. However, Access is strangely absent. He is mentioned by other characters in other comics, such as Superman/Fantastic Four and Superman/Silver Surfer. However, in 2004's Avengers/JLA, by Kurt Busiek and George Pérez, Access is never mentioned once. In effect, he has been all but forgotten, never being mentioned once in the storyline.
On one hand, one reason Access might have been eliminated is due to how his presence draws attention away from the DC and Marvel heroes. He ultimately becomes the main character in each crossover he's in, which means his actions, and not so much the main heroes, become the driving force of every story. That's a practical reason why Access might not play a role in later crossovers.
The other reason, however, might be due to how, over time, the mythology surrounding the Brothers was phased out. This is especially true in the canonical Avengers/JLA comic, which DC continuity would later treat as canon. Considering the complex nature or the comics he appeared in, he and the other characters that debuted during Marvel versus DC, including the combined Amalgam heroes haven't resurfaced in any kind of official capacity, and they likely wouldn't be able to outside of a co-production from Marvel and DC. But regardless of why Access disappeared, he ultimately did, and he left several iconic crossover comics behind him.