Luc-Jean Lavin, better known as "Captain Lavin", is a celebrated Cosmonaut and diplomat. He is currently the commanding officer of the Cosmonauts. He is deeply moral, highly logical, and intelligent. Lavin is a master of diplomacy and debate who resolves seemingly intractable issues between sometimes implacable parties with a Solomon-like wisdom. Though such resolutions are usually peaceful, he is also shown using his remarkable tactical cunning in situations when it is required.

Captain Lavin is credited with making first contact with no fewer than 27 alien species, including the Avocadians and the Blueberrians, becoming earth's chief contact point with Guac-9 (which Avocadists have contested for centuries).