The second detail was more surprising. Fero seems to have an affinity with Darkness!
It was faint, but Lee noticed it's fur turning pitch black at some point. When Lee teased the beasts to chase him and catch him if they can, the beasts put their everything into it, and Lee witnessed this vague transformation.
His heart was filled with joy, as he had never expected his two familiars to develop two lethal affinities. Lightning, as we all know, was capable of disintegrating it's opponent. Darkness enables anything to be one with the shadow and darkness, and to execute silent killing sprees!
Lee took a glance at the Map and two boys approaching the stadium door. One had a magic staff in his hand, and the other had a spear. They were dressed appropriately for training and their intention was found friendly by Lee.