personalityThe content below probably makes no sense whatsoever. I am not a psychologist and i dont really know how to analyze fictional characters. So please bear with me. ^^;
Put simply, Krad has a very complex personality.
I. Krad seems to be very insecure about himself, and his relationships with others. I think this is because Krad has never had an actual relationship with someone. (That we know of at least) When we see him interact with others, he seems to just hate them. But that is most likely, not the case. I think that this shown 'hatred' is probably some form of frustration. I'm not entirely sure about this though. ^^; -Is not a therapist-
II. Krad has yet to show us some sort of 'soft side'. Contrary to what some believe, in volume 9 when 'Krad' expresses envy towards Daisuke that is actually Satoshi. (I'm pretty sure, at least) What hints to it being Satoshi, is the ring Kosuke gives him earlier in the chapter. The ring allows Satoshi to 'control his shadow'. Meaning that Satoshi control's Krad while he is transformed into Krad. But i believe Krad himself, probably envy's Daisuke a bit. Being able to live a normal life and get along with others.. i believe that is what Krad really desires.
III. In response to the above, we now have reason to believe that it was Krad, not Satoshi who appeared in said chapter. We can think this because in the most recent chapters, Satoshi uses the ring to bring forth Krad and save Risa from falling to her death. The ring can only be used once, so I therefore, it must have been Krad speaking and not Satoshi. Meaning we got a small glimpse into the softer side of Krad. Unless, of course it was Krad that saved Risa by his own will, but that is very unlikely. While reading that chapter it is pretty obvious that Satoshi just used Krad to save her. Saying that it ‘Didn’t hurt this time’ when he called Krad out. This is more than likely because Satoshi has feelings of love towards Risa, and those feelings are what bring Krad (and Dark, for that matter) forth.
IV. While I like to believe that the above is true, I will also explore the possibility of Krad himself saving Risa of his own will. Honestly, I do not even know where to begin. Krad has had no interaction with either twins on his own behalf, it was all Satoshi. I do not believe it is possible for him to develop feelings for one. It would certainly provide an interesting twist, and a love triangle on top of that! But it really just does not seem plausible. To add one more thing, the idea that Satoshi has feelings for Risa is nothing new. He found excuses to go out with her in volume 4, he has also had scenes with her which are quite cute. The development is nothing new, really.
V. Krad is a very possessive person. (This section referring to Hiwatari) But once again, i believe this is because he desires some sort of relationship. But because Krad is so insecure with himself, he probably feels that he needs to be possessive in order to keep what 'relationship' he has with Hiwatari.
VI. Krad is without a doubt, a sadist in some cases, which means that he takes a great deal of pleasure in other peoples pain. This is demonstrated on a couple of occasions, but most notably when he fights Dark while dark is without Daisuke (because Daisuke was taken by the second hand of time). Krad deeply slices into Darks shoulder with Eliots sword, he then comments on how Dark should enjoy the pain. Because it is his and his alone. Krad seems to take different stances depending on who his opponent is. In the case where he is thrashing Daisuke, he seems very serious and determined about what he is doing. It is indeed possible that Krad simply enjoys being a sadist in his free time and unimportant fights.