Here are the best of best anime which are under 30 episode.This list is made by personal opinion and considering IMDb ratings too.This list does not contain famous anime like Death note, Tokyo Ghoul etc.*Lowest IMDb to Highest*
Riding the bus one day, Sakura Sakurakōji looks out the window to see people being burned alive with a blue fire as a boy her age remains unharmed and stands over the people. When she goes back to the site the next day, there are no corpses or evidence of any kind of murder, just a small fire. When Sakura goes to class, she discovers the new transfer student is the same boy she saw the day before. Sakura soon learns that he is Rei Ōgami, the sixth “Code: Breaker,” a special type of assassin with a strange ability and a member of a secret organization that serves the government
Blood Lad follows Staz Charlie Blood, a vampire from the surreal “Demon World” who avoids attacking humans unlike his ancestors. One day, he becomes excited when Fuyumi Yanagi, an ordinary girl accidentally wanders into the Demon World through a portal. The two’s first meeting is cut short by the attack of a demon. Staz goes to stop the enemy and save his allies. However, Fuyumi is killed by a carnivorous plant and turned into a ghost, causing Staz to take responsibility and pledge to help bring her back to life.
She becomes part vampire because when they travelled to the human world once to prevent Fuyumi from fading away Staz makes her drink some of his blood, while Staz is away Franken Stein comes up with a substitute for Fuyumi to drink instead of Staz’s blood to keep her from fading away forever.