Based upon the Undertale trend using both of my oc's, my main OC, Bini Filters, and secondary one named Astro Star based upon their backstory. Astro Star grows up to steal souls as he is consumed by grief after his parent's death, the first soul he takes is his only friend's soul when she refused to hand over dark spells books that would increase his power. (Bini Filters is in charge of Canterlot Castle Library and Archive.)

He was unable to force her soul into his spell out of his own guilt for his actions, he kept her soul, haunted by her ghost as his own punishment as he continued to steal other souls, knowing fully well what he was doing was awful.