Knight of Void would make the worst waiter when petty - not only clients would be served nothing, but you won't be able to pinpoint who is at fault for client not being served.

Serving them Nothing then Serving Lies about not having been the culprit, sounds petty alright. Alternatively, they would be the Cook and not the Waiter/Waitress, and prepare Friend Horrorterror Tentacles to literally Serve Void to the clients.