Sekai de Ichiban Warui Majo

Quinta is an infamous grand witch who has lived over 300 years and is known for her cruelty and killing other witches. She's shrouded in mystery and secrets, but the truth is, she's actually only 16 years old. In an unexpected turn of events, Quinta becomes a bodyguard for Nestor Gilroy, a renowned professor with 5 PhDs, who is being hunted down for his unpublished research. Together, Nestor, Quinta, and her animal companion Feeyo embark on a journey in order to have Nestor's results published.