It wasn't that the kobold chief wasn't strong but for a world class boss, Sato felt that it was quite weak. Though he was indeed on the lower hand of this fight, Sato could still hold on against the kobold chief. If Fudo were to be added to the equation, then beating it wouldn't be so difficult.
True, Sato and Fudo were both level 9 and quite strong but according to the information on the 10th level, going past level 9 was similar to a Carp leaping through the Dragon gate; both species, whether players, NPCs or monsters, would all become way much stronger than a level 9 player. However, the kobold chief didn't seem to be doing a good job proving this point.
Sato didn't know why but he had this nagging feeling that things weren't so simple.