Image by Murase Rintarou
Not recommended for younger folks. There's more blood in this than at your average blood clinic, and the Titans (pictured above) are pretty repulsive.
Author: Isayama Hajime
Genre: Shounen, Action, Drama, Fantasy, Mystery
Serialized in: Kodansha Bessatsu Shounen Magazine
Total Volume Count: 7 (ongoing)
Series Summary from MangaUpdates:
Several hundred years ago, humans were nearly exterminated by giants. Giants are typically several stories tall, seem to have no intelligence, devour human beings and, worst of all, seem to do it for the pleasure rather than as a food source. A small percentage of humanity survived by walling themselves in a city protected by extremely high walls, even taller than the biggest of giants.Kenn's Comment: This one won the 35th Kodansha Manga Award (Best Shounen) and was nominated for the 4th Manga Taisho Award.
Flash forward to the present and the city has not seen a giant in over 100 years. Teenage boy Eren and his foster sister Mikasa witness something horrific as the city walls are destroyed by a super giant that appears out of thin air. As the smaller giants flood the city, the two kids watch in horror as their mother is eaten alive. Eren vows that he will murder every single giant and take revenge for all of mankind.
This one is pretty intense. Fans of action series will really like this one, because action is one this one exudes with absolute confidence. It's very much a series where most fights have the main character and his group of humanity constantly on the losing side. The battles aren't a bore either; the 3D gear sends the characters rappelling like Spiderman or Lost Planet, for those who know what I'm talking about, and they're almost entirely reliant on tactics to win any of their battles.
If you're looking for fanservice, I'd advise you find something else: the most you'll find is a female giant. Even so, the female characters have a good chunk of art of them on Pixiv, for those who are familiar with it.
Anywho, like I said, this one's definitely not for the kiddies; copious amounts of blood and death make this one to really keep away from them.