Edwin Odesseiron is a Red Mage of Thay and a recruitable party member from the awesome Baldur's Gate series of PC games. Alongside Minsc, this Neutral Evil Conjurer is one of the most popular characters to come out of the game, thanks to his raw power (he's the only pure Mage NPC in the secondary games, and the best Mage NPC in general) and his hilarious personality, which is a wonderful mixture of snark, arrogance, crazy and incompetence that makes him highly enjoyable to watch getting smacked down. He is more or less incompatible with Minsc, though, due to plotting reasons.
Most famously, in BG2, Edwin's quest leads to his incompetence causing him to spend a substantial amount of time as an implicitly big-boobed woman. Nicknamed "Edwina" in-universe, this leads to massive amounts of hilarity as the other party members taunt and mock her. Indeed, so much fun is had with "Edwina" that in Edwin's epilogue for completing Throne of Bhaal with him in the party, his fate is to be transformed permanently into a woman when he dares to pick a fight with Elminster, after which she spends the rest of her time as a barmaid somewhere in Waterdeep.
Edwina also makes an apparent cameo in Dragon Age Origins, but details are sketchy.