Lasslanlin was a male Orion pirate in the 23rd century, who served as helmsman aboard the RRV Queen Mary, serving under his cousin, Krulmadden.

In 2269, Lasslanlin and another cousin, Artinton, engaged in a barroom brawl on Rigel VIII against Hikaru Sulu and Pavel Chekov. Lasslanlin was beaten to unconsciousness, necessitating time spent in the ship's medic booth. (TOS novel: Prime Directive)