Lust (ラスト, Rasuto), the "Ultimate Spear", is the first homunculus to be introduced in the series. She is a big-busted woman who primarily works in the shadows, acting as an envoy for her leader in both mediums and encouraging alchemists down her desired path. She is able to extend her fingers to great lengths and can use them to cut through any substance. In the manga, after leading an effort to capture Barry the Chopper, her plans backfire when Roy Mustang infiltrates the homunculi's secret lair. Though she is able to severely wound Mustang, he sears his wounds shut and then repeatedly burns her to death, ultimately killing her by depleting her Philosopher's Stone.

In the anime, Lust was created when Scar's brother tried to revive his dead lover. Though originally largely the same as her manga counterpart, Lust begins to crave becoming a human as the series progresses. This leads her to defecting from the homunculi and joining sides with Edward Elric under the condition that he help make her human. She is ultimately tracked down by Wrath who, after paralyzing her with a locket that contains strands of hair from her original body, kills her.

Source: Wikipedia