Leo's strange move immediately caught Raphael's attention. He knew what that technique was, but he himself hadn't had time to learn it.
Before, he was so focused on breaking the record for fastest training to level ninety that he didn't spend time practicing high-level energy control.
This technique is very hard to learn because it takes forever, but the result isn't that appealing.
The effect is just adding an extra layer of armor to your body. How strong or weak that armor is depends on how much energy you put into it. Compared to defensive-type techniques, it's way worse, so it's pretty useless.
Aside from techniques, you could just make a good set of armor and follow a contractor with strong enough support abilities, which would be way more effective and save a lot more time.
Most people who learn it are those who've reached level ninety-nine and have nothing better to do, so they go train this technique.
