|“|| My duty is to protect Kieryn, but also to defeat them.|
– Darkness Cerberus
Not much of Cerberus' past is known. The only known thing is that he once served the Chaos Empress, Eris and as leader of the Mythic Beasts. After many years, eventually came into the hands of young Chrystal Rey. Cerberus bonded with Chrystal about two years prior to the start of the series, being her only friend while at Neos Academy.