The Drakh are a secretive race believed to be closely aligned with the Shadows.
They have some psi ability and telekinetic power, and frequently plotted unseen against the Minbari (leading to a civil war) and against Earth Alliance members during the Martian Civil War.
Later they controlled a Centauri leader in secret and built up the Centauri military leading to a war between the Centauri, Narn, and Drazi.
In 2266 the Drakh attacked Earth with a Death Cloud. The Cloud was destroyed, but released it's virus into the atmosphere, but a cure was found just in time to prevent all life being wiped out.
In 2278 the Drakh presence was uncovered on Centauri Prime and they were driven out, pursued by Centauri and ISA ships.