Leo Kosmokos is one of the pre-made exterminators who resides in Riverblossom Hills, the neighborhood shipped with The Sims 2: Seasons. The other two exterminators are Barbara Carr and Gabe LeTourneau. He can be made playable by befriending and asking him to move in, or by marrying him.
Leo has short black hair, grey eyes and medium skin. He is mostly interested in Fashion, Travel, Crime, and Sports. When it comes to Leo's skill points, he has maximized the cooking and creativity skills, and is halfway towards maximizing the body skill. Leo has the same facial structure as River Pons.
Sometimes if he is made playable, his PlumbBob will be inside him, instead of above his head. This happens with several other NPCs in The Sims 2. Unusually for a pre-made NPC, Leo has the memory of meeting another NPC, as well as having a pre-set relationship with her.