Hearing Rainn's words, Dynosa immediately jumped back and put on alert. Rainn already knew now.
His special abilities weren't that hard to figure out for a mind that was smart enough. Dynosa knows that. That's why he launched his attacks as fast and as strong as possible with the intention that he would kill Rainn before he figure out everything.
Dynosa did that because he was facing Rainn Haryl. Hunters who seem to have limited abilities and have many types of Magic powers.
Never before had anyone been able to match his strength. Once Dynosa's enemies figure out how his powers work, they'll only be left in despair.
Because they couldn't possibly find a way to counter his ability to turn back time. Although the rewinding time ability could only apply to himself, it was sufficient.
Dynosa can rewind the time when he almost died and return his state to a few seconds before.