The founding titan or primordial titan was acquired by Ymir Fritz about two thousand years ago, and was the first titan to exist. He is considered to be the most powerful of all nine original titans, and the one who gave birth to all other titans. Since Ymir Fritz died thirteen years after inheriting the original titan, none of his future wielders were able to possess the founding titan any longer than that, with their bodies deteriorating as the time limit approached.
To give you an idea of how powerful the founding titan is, he can transform any descendant of Ymir into a pure titan and control them in any way he wants, he has the ability to change the minds and memories of all Ymir's subjects and he can still communicate telepathically with all of them. And one of his most incredible abilities is the ability to summon the ancient wielders of the original nine titans from any era and manipulate them like puppets.
By my count, there are nine known carriers of the founding titan and in this video you will get to know a little about each of them.