Maby I am the only one who thinks so, but this story feels super cliche.
The Hero who don't want to hurt anyone.
The Stupid sister who can't do anything without here brother.
The villain who is super evil and has zero deapht.
Everything feels like something i read a 100 times ┑( ̄Д  ̄)┍
The hero literally don't care about hurting someone as long as he himself deem them deserving, the villain is scared shirtless of everything and will destroy everything to fulfill the need to be safe, the sister disarmed a bomb by herself. It does hold major cliches, I see similarities to some great zombie mangás, but not like you put, though.
I dont like the main Villain, he is so pathetic and forgettable. I thought he had more to offer ╮( ̄▽ ̄)╭
Just like his ancestor, the family of forgettable backstabbers who run when things get difficult/don't go there way