Another divine flame: Heaven-Devouring Flame!
Although Bai Zemin was not using Soul Manipulation and thus Overlap Regeneration only allowed him to exchange the points of one stat for another instead of the double effect the skill would have with Soul Manipulation doing its job, the power of Overlap Regeneration was undeniable; particularly in the hands of a powerful soul evolver.
With nearly 14,000 Strength points, added to the attack power of Annihilation of the Falling Sky plus the weight of its greatsword form, counting the falling force from the sky with the gravity increased x30 times, and adding to all of this the 20% increase in attack power that Crimson Flame granted Bai Zemin... One could only try to imagine how powerful his charged attack would be after activating Rumbling the 'Heavens, Shaking the Earth'.
All this without mentioning the fact that Bai Zemin was using the power of the Endless Blue Lotus Flame and not to mention the fact that he was aiming directly at the enemy's weak point; the head!