Also known as the Fenris wolf and Fenrisúlfr. An obvious terrible beast, he was not killed due to an agreement between the Aesir and the Vanir not to slay their offspring. In other tales of the Nordic Sagas, Fenrir was ensnared by the dwarves who forged Gleipnir. Supposedly, he ocassionally escapes to roam Midgard to wreak havoc and to search for prey. Mortals recognize these times for the Avatars of the gods wander about to search for Fenrir. During Ragnarok, Fenrir is ripped in half, quite literally, when Vidar places his foot on the wolf's lower jaw, and proceeds to tear the upper portion of his jaw over his body with his bare hands.
Fenrir is also the name of many powerful server boxes (as is with most Nordic proper names), and an Esper in Final Fantasy VI, and makes his appearance with many other RPG's.
Point of rhetoric: Why are Fenrir and other anthropomorphized creatures categorized under "thing?" Fenrir is not an inanimate object, has a gender, and is intelligent as well. Intelligent enough to fool the gods, escape Gleipnir, and maim that dumbass Tyr.