Halion is a powerful dragon boss in the popular online game World of Warcraft. He is the final encounter in the Ruby Sanctum, a raid instance introduced in the game's Wrath of the Lich King expansion. Players must work together to defeat Halion, who has both a physical and a shadow form, requiring strategic coordination and timing. Halion is known for his unique mechanics, including the ability to switch between light and shadow phases. This adds complexity to the fight, as players must adapt their strategies based on his current form. Defeating Halion rewards players with valuable loot and achievements.