Our Blood Oath (manga)

Bokura no Ketsumei is a Japanese manga series by Kazu Kakazu.

Plot
The story of Our Blood Oath follows brothers Shin and Ko Hizuki. As a child, Shin was taken in by a Vampire couple and not too soon after, that couple had Ko. Then, a long-haired Vampire appeared and killed the couple, leaving only Shin and Ko alive. This was when Shin made a Blood Oath Of Darkness with Ko and he swore to protect his little brother forever. They live in a world of Vampiric Beasts, starved Vampires that turned into monsters, and they feed on human blood to survive, all the same with regular Vampires. Ever since the tragedy that befell the Blood Oath Brothers, they have been striving to form peace and coexistence between humans and Vampires.

Volumes
Volume 1: Blood Oath Brothers

Chapter 1 - Blood Oath Brothers

Chapter 2 - Home Alone And Lost Children

Chapter 3 - Overflowing Love

Chapter 4 - A Mysterious Candy Shop

Chapter 5 - Izuki Nishiyama

Chapter 6 - Unyielding Bonds

Chapter 7 - Delivery And Menace

Chapters Not Yet In Tankōbon Format
Chapter 8 - Becoming The Beast

Chapter 9 - The Long-Lived

Chapter 10 - Fascination

Chapter 11 - Versus Haiga

Chapter 12 - A Greater Foe

Chapter 13 - Power