A stranger from the years of Nightmare Invictus’ reign, who ultimately awoke the slumbering Queen Glados and aided her in retaking her nation on the condition that she’d get something from her in return.
 
Very little is known about the mare known only as ‘Chell’ - her motives, her family, or her origins. Unusually enough, while having been recorded for at least forties years, hanging around close to the royal family and having a peculiar connection with Wheatley, Chell is stated to have never physically aged during that period and always appearing as a mare in her twenties, and the kirin deities had all noticed something ‘odd’ about her soul.
 
Hard-headed, vindictive, and abnormally stubborn, Chell never gave up; she came across as callous and cold, and was never known to have been truly ‘friendly’ with anyone. To her, other ponies were simply a means to an end, and she never had any trouble casting aside others without a second thought.
 
After Nightmare Invictus’ exile, Chell vanished, and was never seen again. There have been some rumours as to what happened to her, but Glados has been adamantly silent on the matter.