Eren flew against the winds to reach the Phoenix which was falling. However, the speed at which he flew surprised even him. It was much faster than his speed in the human form.
In the dragon form, his bloodline skills had also strengthened. More than that, it was his stats that surprised him. All his stats had become stronger in this form and he could feel it.
Another thing that surprised him was the entire transformation itself. He had thought that it was going to be painful to transform.
His entire body had to deform to transform into the dragon form, and it should have been a painful process. But that wasn't the case. It wasn't his body that transformed.
He felt like he was still in his human form, but the Sea Dragon's essence had formed a new body around his human body at core.
There were a lot of questions about this transformation in his mind, but he focused on the Phoenix.