"Yeah, it's been a long time, Black Zetsu." Shimura Danzō openly acknowledged his identity. At the same time, beneath his mask, the black tomoe within his Three-Tomoe Sharingan scattered, then reassembled into a new pattern—the Mangekyō Sharingan of Shimura Danzō.
"So it really is your Mangekyō Sharingan." Black Zetsu recognized Shimura Danzō from the pattern of his Mangekyō.
"You actually didn't die at the hands of Shisui Uchiha? To escape from him, you relied on..."
Even Nagato had failed to emerge unscathed from Shisui Uchiha's hands, let alone Danzō.
Black Zetsu understood the Uchiha Clan's eyes even better than the Uchiha themselves. Higher-level Sharingan possessed absolute suppression over lower-level ones.
Though Black Zetsu still did not know whether Shisui Uchiha had truly awakened an Eternal Mangekyō Sharingan like Uchiha Madara's, something capable of contending with Nagato's Rinnegan could not possibly be an ordinary Mangekyō Sharingan.
Then Black Zetsu suddenly recalled the ocular technique in the other man's right eye and immediately understood.
"Throughout history, at least dozens of Uchiha Clan members have awakened the Mangekyō Sharingan. This is the first time I've seen an ocular technique like the one in your right eye. But it was precisely that technique that saved your life." Black Zetsu scrutinized the other man's Mangekyō Sharingan as he spoke.
"Yes. It was because of that ocular technique that I escaped from Shisui Uchiha. And because of that same technique, I lost my other half." Thinking back on the past, Danzō was filled with emotion.
It turned out that before his battle with Shisui, Shimura Danzō had used the Mangekyō ocular technique in his right eye, Shivama: Proliferation, to split off another version of himself and hide it away.
Thus, Shisui Uchiha had only destroyed "half" of Danzō that time. He had not eradicated Danzō completely.