Halo is a gestalt of a human body an energy-being resembling a sphere of iridescent color. When sociopath Violet Harper was murdered by Syonide, an operative of the 100 and Tobias Whale, the Halo, who had been observing her out of curiosity, was sucked into the newly-vacant body, which it found itself animating. The shock of death-and-resurrection induced a profound amnesia in the new combined entity. As such, she was a complete innocent who was discovered by Batman who recruits her for the Outsiders. The character's presence has extended beyond his origins to Clothing and Accessories , Bags and Briefcases Hats , Keychains ,Outerwear , Scarves and Ties ,Shirts,Watches, Collectibles,Chess Sets , Miscellaneous products, Sculptures ,  Desk and Book Accessories, Bookmarks , Calendars , Journals and Stationery , Sheet Music ,Bedding , Home Decor , Mugs & Glassware ,Ornaments ,Wall Hangings , Jewelry, Bracelets , Earrings , Necklaces , Pins , Rings ,Watches , Party Bundles, Posters & Prints,  School Supplies, Bags and Briefcases , Bookmarks , Journals and Stationery , Lunchboxes , Toys & Games, Action Figures, Diecast Figures and Sculptures, Chess Sets, Dolls , Games , Plush , Puzzles and Trading Cards. Regardless of her state of mind, Halo later has adventures in which she had to deal with the consequences of her body's previous occupant's actions, which required the assistance of the team to resolve. In one incident, early in her existence, Halo becomes emotional over the tendency of human beings to kill each other in battle.