@Kevin Julio
Life Essence only increases or speed ups the process of intimacy between his subject and him, kinda like makes them less hostile subconsciously, what you must be thinking of is the blood pact which is the one he used on the maiden back then from the Ten Nations Alliance to forcefully subjugate her loyalty.
And Yu Zi Yu has never made any blood pact contract with any of his beasts so Darkness can indeed sna*** them from him