I never really saw that. To me, she was the hero that was broken by the Survival Game and her loss of Yuukii, and was driven to insanity, but was redeemed by the end of the show.
LOL Well, from her perspective, she was a hero who was protecting her Yuukii. Daaamn, this is why I have trouble saying whether I prefer Mirai Nikki or Death Note. Both have such awesome main characters.