Sirius

Skye's Shiny Umbreon, (Skye's Shiny Blacky), nicknamed Sirius, is the eighth Pokemon obtained by Skye in the Sinnoh region. He was caught alongside his younger sister, a younger Eevee that later evolved into a Glaceon, after being abandoned by their trainer, the evil Team Galactic scientist Charon.

History
After being abandoned by Charon, Skye caught both Sirius and his sister Eevee. He had the distinction of being a shiny Eevee that was very protective of his sister. Unlike his sister, however, Sirius quickly grew to be affectionate to Skye and be loyal to her.

Upon evolving to a shiny Umbreon alongside his sister, who evolved into Glaceon, Skye and Sirius grew closer, causing Glaceon to become even more reserved due to her brother drawing away from her side.

Following her journies through Sinnoh, Skye dropped off Sirius and the rest of her Pokemon at his house, starting with a clean slate for her travels through Unova.