Mismatch

The spar wasn't your typical spar and that was because the opponents involved were not normal either. Any use of weapons was allowed apart from guns. Guns in the first place were a weapon that wasn't used by much in the Reborn group and Zain could understand why.

They weren't effective against demons nor any zombie that was above the 2nd stage. Using them as well would just attract a horde of zombies including the higher stage zombies.

It was best to train the Reborn to use their new talents. As for why weapons were allowed, it again was to simulate a real battle that they might have. Besides, even if they were injured by having a limb cut off or so, they wouldn't feel any pain, and as long as the body part was still present, it could be reattached.

After eating some food, the Reborn bodies would start to heal the detached limb. However, if a body part was burnt as such, then they were unable to regrow that part of the body, they could only reattach it.