Like the Phantoms, the monsters were capable of working as a team and cooperating to achieve a common goal.
That rarely happened among the different subspecies, but monsters preferred not to fight when their common enemies, the Phantoms, were on the battlefield.
However, monsters were not machines or soulless mechanisms, they were creatures of flesh and blood, for the most part. The most important thing was that monsters, even the weakest ones, had intelligence, and the stronger the monster was, the higher the intelligence was.
Sure, intelligence had many purposes, but one of the most important was to have a mind and, as a result - a personality. Thus just like among the Phantoms, among the monsters could appear those whose character, whose actions were illogical, selfish, and destructive.
Obviously, Thunder Demon was one such monster. However, the reason for his behavior was quite simple - he was stronger than the others.
