The Harbingers were able to harness AM in its purest of forms, mainly from the centers of Galaxies. During The Spawn War, they used AM weapons to fight The Spawn, however, the Cores managed to replicate Harbinger technology, and by doing so made them invulnerable to attack, the Harbingers created The Eye from every known element in Havona. The Harbingers, when they died out, left behind AM on their colony planets, one of which is Takreeka.
On Takreeka, 3 vials of AM were discovered by UEM Scientists. They found it and began testing on it in hopes of perfected their still highly imperfect AM technologies, however, in 2086, Takreeka was attacked by Zodiac forces. The Zodiac managed to capture the AM technologies, but not the planet itself, they then began making AM Bombs and incorporating AM Cannons onto their star ships.
The AM Bomb
The Antimatter Bomb is a compact bomb six square feet in diameter. When detonated, its blast radius is six kilometers, and because the bomb destroys all matter including gasses, it creates a Dark Energy siphon, which sucks all surviving ships in a two mile radius into a black hole and destroys them, only one has been used in orbit around one of Mia's Moons.