Kimi no Sei

Kimi no Sei (君のせい) is a manga series by Sakurairo with illustrations by Ami Chatani. There is a sequel under the name, Kimi no Sei - Kizuato.

Kimi no Sei
Takaya has fallen in love at first sight with a girl he saw at his college. The only problem is that she happens to be Yurina, the girl he spent his elementary school days tormenting. While he hardly remembers her from those days, Yurina hates him with a passion. She holds him responsible for all the lasting emotional and psychological scars that were caused by the years he made her life a living hell. Takaya hopes they'll be able to move past their history and fall in love, but can Yurina ever feel anything for him but hatred and the desire for revenge?

Kimi no Sei - Kizuato
Since the prequel, Yurina has set aside her painful memories of being bullied by Takaya, and accepted his sincerity. They're now dating and slowly rediscovering themselves, but their kindergarten classmate Nogi dredges up their past and vows to "rescue" Yurina from Takaya's evil clutches. Will Takaya and Yurina's love — a love that started off on a bad footing — withstand new trials, growing uncertainty and revisits to the past?