Mallory is the current alias of the Schoolchild Tin, from the same batch as Molybdenum. They have the ability to, when sufficiently injured on a physical or mental level, shut down entirely, enter a cryptobiotic state, and slowly regenerate the injury, sealing away memories of a time proportional to the recovery period.
When they were liquidated by Molybdenum, this ability kept them alive for some time. Their partner Pokemon, Axiom, got their body out of the facility, and they escaped the School together. Eventually, Mallory and Axiom agreed that it was too dangerous to even have memories of their School days, they entered another recovery period and Axiom created a false backstory for them as a random trainer, acquiring a handful of Pokemon and wiping their minds as well to sell the illusion.
They proceeded to wander the fringes of the J-team for several years, before being brought back into contact with them in Galar.
Mallory is somewhat truculent, and not terribly helpful in any situation. They try, though.
Mallory is small, slight, and pale, with black hair and the typical purple eyes of School creations. They wear brown contacts to hide them due to a subliminal signal from Axiom.
Mallory is good friends with Avery.