Kerberos Entertainment was established on May 8th, 2014 in Osaka. Its not exactly a record label but it manages vkei bands. It's stated on their website that they plan, produce and manage events for bands (as far as I am able to understand with my limited Japanese).
There's two parts to them: Kerberos Entertainment and Kerberos Children.
Kerberos acts as the main part having had formal bands (BASH!, FoLLoW, ENVIOUS, SweetHome, and Shellmy).
Children supports session bands or individual musicians.
Now here is the confusing thing; formal bands aren't signed to Kerberos but are supported by them. On their website former bands are considered graduates but idk why they are considered so. Their only current band VIVARUSH was a former session band named SECRET under Children.