Jaeger Titan

Jaeger Titans (イェーガーの巨人) are a variety of Titans created through the Jaeger drug. These Titans are able to revert to human form when desired, and they retain human intelligence. In order to transform, an otherwise lethal wound is required.

Implied to be a perfected form of the incomplete experiment which created the original Titans, they were developed by Grisha Jaeger and his assistant, Souda, using information forbidden by the central authority. Using the formula on his own children, one of them was first given to Grisha's eldest son, Shikishima, who gained the ability to turn into the White Titan. The youngest son, Eren, was given the formula next despite harsh protests from Grisha's wife, Carla. Just after, however, the central authority's Military Police broke into the laboratory. Souda hid himself and Eren, as the Military Police led by Kubal murdered Grisha and Carla. Kubal, however, did steal some of the notes and items from the laboratory before it burned down, giving himself the power to turn into the Colossal Titan. Years later, Eren would unwittingly unlock the ability to turn into a Titan form of his own, becoming a rogue, Mysterious Titan.