Seifer Almasy is a classmate and rival of Squall, who can only be controlled by the player during the Dollet sequence. He reappears as a boss later in the game. He acts as a foil to Squall in many respects, having dated Rinoa before she met Squall, and assuming a leadership position among his friends. Like Squall, Seifer wields a gunblade which he calls "Hyperion". His Limit Break, Fire Cross, allows him to use an attack called No Mercy. He later uses the more powerful techniques Demon Slice and Bloodfest against the player. Seifer has a short temper and is often depicted as a bully who desires attention. He is also fiercely independent and is often punished for his recklessness. He is the leader of Balamb Garden's disciplinary committee with his friends Fujin and Raijin. After joining Ultimecia, he becomes the leader of the Galbadian army.
Source: Wikipedia, "[en.wikipedia.org/wiki/Characters_of_Final_Fantasy_VIII%23Seifer_Almasy Characters of Final Fantasy VIII]", available under the CC-BY-SA License.