Seraph of the End
The world has ended. Every adult across the planet died off in an instant due to an unknown disease, and those who were young enough to escape the pandemic have been captured and herded into holding facilities by powerful and ruthless vampires. Yūichirō, one such survivor, strives to escape his imprisonment alongside his adopted siblings, but is met with tragedy when they are all decimated in the escape. Luckily, he is rescued by a human resistance faction looking to free humanity and restore order to the world, wielding demonic weapons capable of slaying the newly risen vampires. With a renewed hope and a need for revenge, Yūichirō takes up his own possessed weapon and sets out to bring vengeance on his family’s killers and bring peace back to the remaining humans of the world.
Though a bit slow to start, the series is more than capable of going to the brink of Shonen insanity with tense battles and insane attacks on the level of shooting tiger ghosts from a sniper rifle. There’s also the chance of more episodes coming in the future, thanks to the manga’s continued publication and popularity.