Baron Core is Baron's remained and deformed state when his Spirit Core was destroyed by a enraged Samuel Nakaoka the Second in his BEAST King form. Kumon's hatred, however, will not die that his hateful essence directly towards to Digimon World and starts to revive himself in order to kill both Samuel Nakaoka and Kolda once and for all due to his hatred towards Samuel Nakaoka who killed him.
Enraged by Samuel Nakaoka destroys the lab, Baron absorbs the deleted Digimon's data that the DigiDestined defeated them only Beerus destroys the conversion machine; causing the conversed mechanics are gone haywire to form his incomplete state to tries to kill Samuel Nakaoka the Second.