Ryu's Magus Lock threatened to collapse entirely. Just in case, before he had split his soul, he underwent a great deal of trouble to rebuild and reconstruct his Magus Lock. With his talent, he was already infinitesimally close to the Soul Quintessence Realm, at least in terms of the size of his Spiritual Sea—when his soul wasn't split in two, that is. Even so, the Magus Lock he had on right now was the representation of the best of his abilities, and yet half of it had collapsed due to a single attack.
Much like the change to Cosmic Qi after the Cosmic Seed Realm, entering the Soul Quintessence Realm allowed a qualitative change in one's Spiritual Qi that was impossible to fight against with quantity alone. Ryu had plenty of quantity, but when it came to quality, it was several steps behind Pierthorn.
