The Brothers "Dee" and "Marv", otherwise known simply as "The Brothers", are the cosmic personifications for a multiverse segment otherwise referred to as D52-M616.
The "Brothers" are very protective of their multiverse segment, even going so far as to send out their own Multiverse agent to go after any entity in other multiverses that are similar to their own.
"Dee" and "Marv"
The Brothers are huge cosmic entities that came into being when their respective universes did. Those universes then spawned off other universes within it, and the entities became more and more powerful in the process.
Agent Asher is the humanoid agent that The "Brothers" use to persue aspects of other universes that are too similar to established aspects within the D52-M616 collective. He is a no-nonsense operative whose presence spells doom for any being he is there to eliminate.
Agent Asher carries within him the full power of the "Brothers", and thus is considered a true Omega-Class being.
(See also "Access")
The "Brothers" and their agent were referenced in the text-only "Guardians of the Dawn Spotlight" #0.