A while ago.
Felix had been overwhelmed by the enemies. His enemies consisted of four King Class Monsters like Rea. In terms of fighting ability, he was better than Rea. But to defeat four King Class Monsters, Rea's brain was better since the battlefield didn't consist only of them.
Felix looked at the four King Class Monsters in front of him. The fight had just started not long ago, but his body was already covered in wounds.
As an assassin, he usually waited until the right moment before assassinating the target. But in this situation, he couldn't do it. They had been outnumbered already. If he didn't show himself, the enemies would have overwhelmed them before he could do anything.
Whenever he fought straightforwardly, he would be at a disadvantage, considering his abilities and experiences mostly came from assassination.