In episode 50 of the Attack on Titan anime, Eren blocks one of the wall holes with his crystalizations powers. Do Eren's crystalization powers come from the Attack Titan or from the Founding Titan?
2Very first time Eren uses hardening power during rod raiss arc.. at that time he drank a liquid and after that he is able to use hardening.. I think that liquid must be something that helped Eren– Ichigo KurosakiMay 30, 2019 at 6:10
@IchigoKurosaki is right, and it's from episode 45 as per the Fandom wiki.– TheGamer007May 30, 2019 at 14:32
In episode 45, Eren bites down on this "armor" bottle, and after that, he is able to transform into a hardened titan. Because be got it from a bottle, and did not develop it by himself we are unable to know which titan he developed it with. Though I imagine that if he didn't gain hardening through the bottle I think he could have developed it through practice. (speculation on my part)
Eren can use the abilities of the founding titan only when he's in contact with someone among the royal bloodline. Thus all abilities Eren uses during combat is from the attack titan.
This was confirmed when Erin encounters the titan that ate his mother in season 2 episode titled "Scream", he was able to control all the other titans with his scream as he touched her. That was the only time till date Eren was able to use the founding titans abilities.