After accidentally being sent to the Medieval era Crono and his friends find that Demi-Humans are attacking humans on behalf of the Dark Lord Magus. In an effort to help Crono and his friends join Frog, a knight given Frog like appearance by Magus and they march off to defeat Magus and his generals commanding the army. Once the heroes make it to Magus's Castle they encounter Flea along with his two team-mates gaurding Magus personally. Flea fools the party at first having them fight a stand-in who they mistake for Flea. After his monster fails though Flea appears to attend to them personally. Upon first glance Flea is mistaken (easily) for a woman. Flea laughs it off and playfully admits to being a cross-dresser before entering battle with the heroes. Flea is defeated and the heroes go further in to fight Magus. Magus seemed less concerned with the invasion and more interested in a ritual he was preforming to tear a whole in time. The battle with Magus disrupts the rite sending Magus and the heroes hurdling through time. Flea and her two team-mates though wounded were still alive though and would pick up the pieces of Magus's plan.
Much later in the game when the heroes actually gain the controlled ability to travel though time they can return to the Medieval era possibly with Magus as a ally if they accept his offer to help. When the heroes return they find that a new Demi-Human castle has been built. Apparently Ozzie had decided to claim the role as the new high-commander of the Demi-Humans and had bought-out Slash and Flea's loyalty to him with Magus gone. Even if Magus returns Flea is loyal to Ozzie by then and has no more use for his former master and is only concerned with using the prestige Magus afforded him to rule over the Dem-Humans and help Ozzie overthrow the humans as the dominant species. Flea like Slash is loyal to the Demi-Human cause and not to Magus in particular but is still willing to risk his life to protect Ozzie who has taken over for Magus, Flea's loyalty is not returned though and when he falls defending him Ozzie abandons his friends and runs away. Flea along with his team-mates can be encounted in the sequel game, Chrono Cross. In Chrono Cross the three are fought on the Bend of Time, a small island that exists just on the edge of time.
Flea is vain and obsessed with appearances. He makes fun of the heroes for looking spotty and dull and is very self-centered about his looks. Flea fights with many fire based moves and is an admirer of the beauty of flames. Flea has an enchanted kiss that he uses to confuse the party members. The kiss confuses both male and female protagonists and he does not seem to care who he uses it on, this could mean in addition to being a cross-dresser Flea is bi-sexual though it is entirely possible from his vampish demeanor he is just using his looks to his advantage to toy with his opponents and nothing more. When fighting, Flea uses lots of flash and flare to alter the battlefield's appearance, a testament to his need for extravagance.