Lethargic Lad is the main character. He suppose to be the protector of Infantino City. He has the "power" of lethargy, which causes him to inactive and slow. He rarely talks, but instead utters "Umm..." His alter ego is Larry Ladhands, a parody of Bruce Wayne. He is rich and lives in mansion, under which is the Lad Cave (a parody of the Bat Cave), where he keeps his various tech.
The only other major character is Sailor Steve. Sailor Steve is a male otaku (a person with obsessive interests) friend of LL. He often dresses like Sailor Moon characters. He knowns a lot about Japanese pop culture (even more than some Japanese people).
My main source was Wikipedia.