Kekkaishi no Ichirinka

Eighteen-year-old Hana Ichise comes from a long line of supernatural guardians, but she's always lived in the shadow of her gifted twin sister. When Hana finally awakens her own immense power, she hides it, desperate for a normal high school life. Her peace is shattered when Saku Ichinomiya, the arrogant and powerful head of her family's main branch, discovers her secret and forces her into a marriage contract. Now bound to a man she barely knows, Hana must learn to embrace her true potential or be consumed by the dangerous world she tried so hard to escape.