You have your characters confused. Bill Mumy's character, Lennier,
is not the station's underground "fixer." His character is Delenn's
diplomatic attache, who has lived virtually his whole life within the
confines of the religious caste, and has now been sent to B5. The one
you're thinking of is n'grath, who looks kinda like a 7 foot tall
praying mantis.

jms