Tenebrae shook his head, and turned as it appeared he had killed the serpent, and it's master was chained beyond help. Easy fights were not his style. In his invasion of the Gotie 13, only higher ups, and those crushed by his power were really killed. He found no point in trouncing weaklings. He had left the Soul Society when he had run out of strong people to challenge.
Power lived to clash with other power.
He was....almost sad that it had ended that quickly. The serpents power was not it's own, but it was still a worthy opponent, if it could have concentrated more, it would have been an interesting match.
Power on it's own was useless unless applied right. A thought came in his mind at that point
Then is my power useless?
"No.... as long as I hold power, others will challenge it. By existing, I strengthen the world. This darkness is the challenge the world must overcome to be strengthened, elsewise it would weaken under complacency. I am it's forge."
It was then he felt the explosive buildup of reitsu behind him. That wasn't the power of the downed.
"Face the sum of your life's work, face your sins
As he turned his head, a blur of motion towards him, with Naratsu rushing with a stab to the heart.
Tenebrae took a simple counter measure, and gambit against the attack, using the energy sword which he held to return the gesture to Naratsu, aiming his chest as well, only he simply held his sword out, for Naratsu to impale himself on... by his own speed.
Where as Naratsu's was a high speed charge, he would need both hands to accomplish such a thrust, reducing his range. Tenebrae merely needed to extend his blade forward with arm, giving more range. More range meant Naratsu would be impaled before he had the chance to hit Tenebrae.
This state also left Tenebrae with a free hand, to cast his kidos, and so he did.
"Bakudo 63. Sajō Sabaku."
A chain erupted from Tenebraes fingers.... but not at Naratsu. The chains wrapped around Tenebrae's chest, forming an impressive and improvised armor against the incoming blow, using the chain's strength as a defense rather than a restraint. He would still take quite a bit of damage, but it was insurance against his gambit, incase Naratsu was foolish enough to continue his charge.