Devil Fruits are curious things. After the death of every user, it is reborn to the world, ready for a new person to wield their power. Rarely do two users of the same fruit use it the same way. Such was the case of the recently transferred Mera Mera no Mi.
Sabo took great satisfaction and closure in possessing the powers of his fallen brother. He had instinctively taken to its use, having learned a fighting style to mimic the power of a dragon, what better ability than to generate flame? He used it less as a bursting force as Ace had, not that Sabo had the slightest idea how his long forgotten brother used the Fruit, but more like an extension of his body, enhancing already destructive blows and blinding speed.
But somehow one thing seemed to be the same. When Blackbeard attacked Baltigo, a new attack came to Sabo. He raised one hand and a massive sphere of spiralling flames erupted above him.
"Dai Enkai: Entei Eidolon" he whispered, unsure where the words came from but feeling great sadness as if a memory he never had was bringing tears to his eyes.
As he launched the ball at the Yonkou, the interior of the ball glowed especially red in a sea of yellow and orange.
It lasted only a moment, but it was unmistakable to both its caster and its victim: Within the ball, a distinct form had taken shape, unquestionable. That hat, the shorts and boots, even the mark emblazoned in blue flames on his back. The true Great Flame Commandment: Flame Emperor hit Blackbeard and consumed him. The ghost of flame disappeared as the spherical vortex made contact.
To Sabo, it was the last remnant of the fruit's previous master, and the smallest bit of memory he had of the man, manifesting himself to save his sworn brother.
To Teach, it was one last bit of revenge- one attack the Logia could not so simply absorb.