That different personalities shit is head canon... We shall see from this chapter if Orochi acts ANY differently now.
And also, Who cares if he had multiple personalities. He doesnβt train. His body weak. Get it? There is no such thing as being strong without training in One piece. And Orochi is surprisingly one of the very few characters we know as for sure doesnβt train
Also, are you asking whether for example a hydra, (as in the many headed serpent) getting for example Cut in in the Abdomen instead of the head will survive? Are you saying The Yamata no Orochi can regenerate every body part and not just itβs head? Which Myth did you read that from?