Nathan Delcompte was the first officer of a Psi Corps mothership that Lyta Alexander and G'Kar found dead in Hyperspace in 2262.[1]
Delcompte was recreated as a projection created by the sentient Hive Mind Bacteria for Lyta Alexander on the "Hive Mind" planet.
While exploring the world, Lyta encountered Delcompte, who took her to purported survivors of the Psi Corps ship. With Lyta's Vorlon-augmented abilities, Lyta could touch another telepath’s mind and leave no trace of ever having been there. She performed a light surface scan of Delcompte and discovered he could not possibly be who he said he was. She closed her eyes and was able to break through the false imagery she was seeing and Delcompte and the other telepaths disappeared.