"Hmm, this feeling feels familiar," Ray muttered, recalling the sensation he experienced when he had maxed out his Lord of the Sky skill. He had become one with the sky, and the sky had become him. This was exactly the same feeling he had previously encountered.
It was as if he was molding the very principle of the sky and manipulating it freely, just like this sword.
"Core principle?" This thought immediately appeared in his mind as he contemplated further.
"So, I can make anything into a sword, huh..."
This was definitely not as simple as it seemed; something that his A-class skill could only do when fully upgraded was a similar feeling to this skill.
"Core principles, huh..." Ray repeated to himself while closing his eyes.
"If the core principle of the sky encompasses all things in the sky above the surface of the planet, then what is the core principle of the sword?" His eyes slowly opened as the black pupils seemed to flash.