Mazzy Fentan is a recruitable character in Baldur's Gate II: Shadows of Amn, who can be located during the course of the Umar Hills quest. She was the leader of an adventuring party who was sent to explore the deaths in the Umar Hills before the player and their party arrive. She is mentioned in a diary in the ranger Merella's cabin, and when the party enters the dark forest that surrounds the Shadow Temple, they see a man fall dead; a diary found on his body mentions that he was in her party. Upon entering the Shadow Temple, Mazzy can be found locked in a cell near the entrance. She tells the party about how the Shade Lord has destroyed the rest of her party, including her husband, and offers to join the fight. The shadow of her beloved, Patrick, is seen as one of the Shade Lord's slaves, and if Mazzy is in the party when the Shade Lord is defeated, it is possible to write an inscription in her party's honor on the cleansed shadow altar.
Mazzy is a very efficient fighter, and the only recruitable good aligned fighter in Baldur's Gate II. She starts out with grandmastery in short bows and specialization in short swords, and has personalized weapons of both types: the Bow of Arvoreen and the Sword of Arvoreen. She strives to be as a paladin even though she, as a non-human, cannot be one within the mechanics of the game, and refers to herself as a Truesword of Arvoreen. She has a number of special spell abilities, including Courage, a Remove Fear spell that also boosts saving throws, and the ability to heal herself with Lay Hands.
If Korgan or Valygar are in the party, Mazzy will have several dialogues with them; Korgan appears to have a soft spot for the halfling lass, and Mazzy will attempt to recruit Valygar as her squire. She also has conversations with most of the other recruitable party members, and will speak to the player about her feelings about their trustworthiness. She admires Keldorn, encourages Aerie, and is the brunt of Anomen's jealous ire if they are both in the same party before his Test. She is a little touchy about her size; she will not stand for Yoshimo calling her cute, and takes some time to understand Minsc's compliments about how she is a great warrior despite her small stature (it takes a conversation about Boo's tiny greatness to convince her of his sincerity).
Mazzy has two associated quests in addition to her involvement with the Shadow Temple. Her home and family is in Trademeet, and after she has been in the party for a few days, you will have to go there with her and help reveal the truth about her sister being poisoned by a false love potion. Additionally, if the Copper Coronet has been liberated, a half-ogre outside the inn will insult Mazzy for her size, and the two of them will duel in the pit inside the inn. In this fight, it is possible to cheat by arranging for the half-ogre to be poisoned - but Mazzy is fully capable of holding her own without cheating.