Rani VIII is the Master of Berserker in Fate/Extra.

She is a young girl who appears to be of Indian descent with wavy light purple hair with part of it tied into a ponytail. She has purple eyes, a tan complexion, wears glasses and has a bindi on her forehead as worn in India.

Rani is a homunculus created by Sialim Eltnam Re-Atlasia with the intention to see if it was possible for not just alchemists, but for humanity to continue existing in the cyber world.
(Source: TYPE-MOON Wiki)