Rezdan is human specialist mage and one of four adventurers, led by Drasus, encountered during Baldur's Gate. Their group has been hired to defend the Cloakwood Mine from "anyone that is foolish enough to challenge [them]" - namely, Gorion's Ward.

Upon turning hostile, either by being attacked or after the player speaks with Drasus, Rezdan starts off casting Mirror Image, after which he'll most likely cast Monster Summoning I, usually followed by Horror - if his colleague Kysus hasn't already. Otherwise, he'll fall back on low level damage-dealers such as Melf's Acid Arrow and Larloch's Minor Drain. He also has Haste memorized, but it isn't a high priority spell, and he likely won't get the opportunity to cast it.

You got somethin' comin', pal. Just you wait.