Blood Blockade Battlefront (Japanese: 血界戦線, Hepburn: Kekkai Sensen, lit.'Bloodline Battlefront') is a Japanese manga series written and illustrated by Yasuhiro Nightow. It revolves around a young photographer named Leonardo Watch, who obtains 'the All Seeing Eyes of the Gods' at the cost of his sister's eyesight. After the incident, Leonardo moves to the city of Hellsalem's Lot to join an organization known as Libra to fight several monsters as well as terrorists.
Nightow first published a one-shot chapter in Shueisha's shōnen manga magazine Jump Square in May 2008. A three-chapter series, with the subtitle Mafūgai Kessha, was published in the same magazine from January to March 2009. Blood Blockade Battlefront was later serialized in Jump SQ.19 from May 2010 to February 2015, when the magazine ceased publication; Shueisha collected its chapters in ten tankōbon volumes. A direct sequel, titled Blood Blockade Battlefront: Back 2 Back was serialized in Jump SQ.Crown from July 2015 to January 2018, when the magazine ceased publication, and the series was transferred to Jump SQ.Rise, where it ran from April 2018 to April 2022; its chapters were collected in ten tankōbon volumes. A third series, titled Blood Blockade Battlefront: Beat 3 Peat started in Jump SQ.Rise in October 2022.
A 12-episode anime television series produced by Bones was broadcast from April to October 2015. A 12-episode second season was broadcast from October to December 2017.
In North America, the first manga series has been licensed for English language release by Dark Horse Comics, while the anime series has been licensed by Funimation (later Crunchyroll). Both the manga and anime were well received by publications due to its story and characters.