Demon king's quest
Being a demon king didn't mean one was just powerful, or born with natural power. Although there was perhaps some talent involved, they weren't born this way. Just like the vampires, the Durum demons were a simple existence and through many of their kind being produced, stronger ones eventually appeared and this was the same for Kronker as well.
Because of this, he had been through many battles, all of them in the current world they were in. Still, he was sensitive to energy and could tell the person in front of him had a large amount of energy that was affecting the whole planet that they were on.
'This energy, it's not only large, but all of it, it's his own energy!' Kronker thought. 'He isn't using the energy from the air around him, all of this is his own energy. Right now, he has enough energy to match us, the demon kings!'