Eren was fighting with three mini giants at once.
Flesh-altering spell!
Eren was using the spell he had learned from Bulal Blood for the first time. He used it on his arms and retrieved the Beskar sword.
The Beskar sword was a heavy sword that was part of the Hex gear set. It was more than 50 pounds in weight and wasn't easy to use. So Eren had never used it.
However, Bulal's flesh-altering spell made his biceps abnormally large. The spell allowed him to carry and swing the sword with ease.
Blitz Steps
Eren cast his movement spell and disappeared from his place, leaving the trail of lightning behind him. Usually, his stride wouldn't leave a trail. But since the sword he was carrying was so heavy, it affected his movements. His steps had become more prominent, cracking the ground beneath them every time he used the movement spell to spring forth.
Swoosh!
