User blog comment:B214/Question and Answers 4/@comment-4547267-20141123021837/@comment-1359322-20141127001548

@0017, it's the main personality, like for example Rias' main personality is caring and her love towards Issei, supposing if you split Rias into the four person you said, do you thing Rias' personality will split into like 1 that scorns her servant? 1 that loves Vali and loathes Issei? Or Issei, his main personality is his perverseness, even if you split Isei into multiple type like you said maybe serious Ise, do you think his perverseness would be split? Do you think you'll get something "oh i'm a gentleman, i don't see porn, porn are disgusting, i even find big breasted girls who uses their breast to seduce man as enemies.

So in the end you can't expect the main personality be split and become something different.