Zenkaizer Black is a fictional heroic form associated with the Super Sentai franchise and appears in Avataro Sentai Donbrothers as a special crossover-style character. He serves as a black-colored variant of Zenkaizer, evoking the imagery and legacy of Zenkaiger while fitting into the Donbrothers world. The character functions as a powerful ally and symbolic cameo, bringing extra fan-service, combat flair, and connections to the broader Sentai multiverse.