First of I think the Reiss eat the precious holder as a means of passing down the memories also not just the ability . Second I think the mystery lies on the original Titan creating ability which is not how the mare people do it with needles etc which didn ' t exist in ancient times . How did the king acquire 10 k colossal titans then ? It also doesn ' t make sense since the Titans clans were fighting each other . Which in my mind is Titan army vs Titan army and not 1 Titan with mindless Titans vs the same . Which brings me to my next pointTitan behaviour is just strange . They ' re attracted and just want to eat humans ? Why ? Because they are desperately looking for balance which is control . They don ' t need to eat humans , they ' re searching for the shifter ability and that ' s why they are even more attracted to shifters . Why is that a thing ? Because of the Mare people meddling with Titan powers which would also explain why Zeke looks like the doll he had in his hand . His power doesn ' t represent one of the 9 abilities . But the fluid he took was genetically modified . Maybe the ability is speech . I believe there are different ways of passing down and giving Titan abilities but we just don ' t know yet .