Raniel crouched low enough that his forearms were almost touching the ground. Using his low center of gravity, he twisted his core and unleashed a one-two hook punch at Satoshi.
The attacks were so sudden that Satoshi missed the right timing. It connected, but Satoshi managed to defend it with his arm guard. If it weren't for his instincts, which were honed over the years, he wouldn't have been able to parry the attack so easily.
Since Raniel decided to fight him with fists, Satoshi used that to decide which fighting style to use. He was going to return the sentiment with the same thing.
An eye for an eye. A punch for a punch.
Apparently, Raniel was pretty riled up for some odd reason— probably because he felt inferior to Satoshi. Then again, it was clear that there was a gap in their proficiency in physical combat, so he couldn't help it.