"System, I chose the Law of Space!"
The reason behind Ace's decisive selection of the Space Law over the Sin and Fire Laws was that it wasn't any weaker than the Fire or Sin Laws.
Moreover, since his inner world can be turned into a real world, something deep inside him made him feel he needed Space Law to further consolidate his foundation. Not to mention, it can grant him far more benefits currently, especially when it comes to his profession as a Thief!
'CRACK!'
The moment Ace chose the Space Law, right at that moment, a crack appeared in the center of the world.
Ace's expression changed. 'Is this the World Core? No! It didn't seem like a crack in the World Core, but a crack in the world's original structure! It's evolving!'
Ace immediately understood what was happening as he remained calm and focused on following the Architect of Thieving Heart Cultivation Technique.
