Chase Mason Hunter is an Eldian from outside the Walls and a prisoner of the miltiary, who just so happens to be the one of the few Titan Shifters left in the Walls. He is The Current holder of The Attack Titan and the Armored Titan.
Not much is known about Chase, He is said to have been Outside the Walls. At an unknown time, he inherited The Attack Titan and The Armored Titan and smuggled himself into the Walls not short after.
During his time In the Walls, he caused so much trouble that he was imprissoned.