The Orc Hugard is the last NPC that a player will encounter when doing the Unique Mount quest. He can be found on Mount Island. He will send the player upon three quests one after another. The player must complete all three quests successfully which consist of killing a series of T-Mutants upon Mount Island. This is the Unique Mounts quest, and is the quest that must be completed for a player to procure their Special mount.
Since then, Hugart will sell these Mounts.
The complete quest guide can be found in the Unique Mounts quest guide.