The Trinity of Evil are a diabolical trio of powerful fallen angels and villians from Chaos! comics. They first appeared in the Chaos! Quarterly miniseries, and served as the main antagonist of the 1997 Cremator miniseries.
The Trnity of Evil were once three angels, Belial, Mephistopheles, and Asmodeus, who rebelled against God 10 billion years ago (This was referred to as the second civil war in Heaven, the first presumably being that lead by Lucifer ) because they did not beleive that they should bow to mortals.
The Trinity was than sealed in the Nethwerworld, where they devoted their lives to descovering forbidden knowledge. They built large structures in the netherworld, and eventually came to lead the countless Wraiths of the netehrworld, as well as their queen, Zaphora. They were also involved, somehow, with the imprisonment of Apolyon .
The Trinity was able to cause massive destruction in Hell, but were eventually faced with a vengeful Apolyon. The two ahd an epic Battle that destroyed a large amount of Hell (as well as several cosmic bodies that were summoned for use as weapons), Their battle was stopped short by Cremator , who attacked them with the spear of Destiny, killing Belial.
Mephistopheles was then killed by Apolyon, and Asmodeus used his last strength to kill Apolyon.
The Trinity Of Evil, as angels, were already massively powerful before their quest ofr forbidden knowledge. Their ten billion years of study, however, gave them a much larger power. They were abel to act as a single entity, saying enchantments not heard for billions of years and necrotic shields as massive as stars.