Why Ymir jaw titan and Galliard jaw titan look so different? Ymir jaw titan looks rachitic, when Galliard jaw titan looks bulky.
Ymir jaw titan

Galliard jaw titan

I didnt even recognize the jaw titan when I saw it in the last season of the anime. Why is this so? Is there any explanation in the manga or in any sourcebook why Ymir jaw titan and Galliard jaw titan look so different?
Marley nation modifies their titan shifters so they can harden their body. This is mentioned in chapter 95 page 21
That’s why Ymir’s titan form is different from Marcel or Porco. Ymir was an ordinary girl who didn't train in the military like Reiner or Annie.