Shiki is a great manga because it keeps the story personal and closed (if that makes sense).
A series of deaths occur in a village, and it all started after a certain family inhabited an abandoned mansion, it turns out they are vampires. It's a bit slow in the beginning, as it focuses more on world building, but the mistery is ever present, and the struggle of the village is all more enjoyable because of the scale, we know who everyone is and what the village is like, details about the national road, the temples, houses, and we are more invested in the story because of that.
The vast personalities of the characters responding to the terror in different ways makes it all interesting. We have two factions, the villagers who try to understand what is happening, and try to survive; and the Shiki, a group of undead who are responsible for the misery of the vilage, and we care about the fight that happens with both, who will survive and be the dominant species.
The art is the weakest point, I struggled to enjoy it and didn't find me staring at a page admiring the drawings, just finished reading and went to the next page, it lacks detail. But it sets the tone for the atmosphere and it suits the theme.
I was not expecting to be engaged in this series, but the events are well thought out and intriguing, plus you are fully invested in the characters and the fate of the village that you keep on going.