Shielder's True Name is Mash Kyrielight, a Demi-Servant human fused with the Heroic Spirit Galahad. She herself initially does not know the identity of the Servant fused with her. In the year 2000, Mash was created from artificial fertilization and genetic editing. She is actually a Designer Baby, a magus genetically engineered under the orders of Chaldea's late director, Marisbury Animusphere, to be a prime vessel for a Heroic Spirit's soul. The project aimed to control the powers of Heroic Spirits by binding them to a compatible mortal vessel in order to produce Demi-Servants.
In 2010, when Mash was aged 10, Chaldea performed their second Heroic Spirit summoning. While the project succeeded in summoning and binding a spirit to Mash, the spirit failed to awaken. Galahad decried Chaldea's brutal experiments but remained in the world to keep his host alive.
After the research team deemed the project a failure, Mash was left to Chaldea's care. However, due to being a genetically engineered organism not dissimilar to a Homunculus, her life-span was set since her conception. She was given eighteen years to live and while she was aware of this fact, she kept it a secret between herself and Dr. Romani, her physician.
Mashu has lilac hair, lavender eyes and fair skin.
In her casual outfit, Mash wears rectangular frame glasses, a grey hoodie over a black shirt over a white-collar shirt, a red tie, a black skirt and tights and brown shoes. In her Demi-Servant outfit Mash wears skin-tight black armor that resembles an extremely short mini-dress that exposes her butt and reveals her panties. There is a hole that exposes her stomach area. She also wears black gauntlets and boots, a garter on her right thigh, a large cross-shaped shield and she doesn't wear her glasses.
Loyalty: Above 5 digits