Counsellor L'shan was a Drakh Captain and was among those who led the attack on Earth in 2266.[1]
Following the destruction of the Shadow planetkiller, the Drakh released a bio-genetic plague into Earth's atmosphere while the bulk of the surviving fleet retreated. L'shan ship was pursued by the EAS Persephone and eventually forced down on Ceti IV, though the Earth Destroyer itself didn't survive the engagement.
The crew of the Excalibur detected the Persephone's distress pod, and was able to rescue the Interplanetary Expeditions archaeological dig crew from the approaching Drakh and were able to capture L'shan.
L'shan was held aboard the Excalibur and briefly interrogated before being sent back to the plague infected Earth for further interrogation, much to L'shan's dismay.