Cain's eyes burned with red light as he set his Ego Wave ablaze, using its full power to neutralize the energy inside the battle vessel, so the Soul King could not blow it up. Destroying the fragment of the Soul King present in the Astral Bloodline Realm would surely harm the Dark King's true soul, but sealing it would do much more than that.
After all, even if Cain was not proficient in the soul path, there were great masters in the Deus Behemoth Empire, and any of them could use the fragment of the Soul King to do a lot of damage to the man through curses or other types of skills.
