The atmosphere between Sasuke and Itachi was slightly awkward.
Itachi was still young, while Sasuke was already the father of a child.
They were clearly brothers, yet the younger brother was far older than the elder.
Sasuke had experienced more than Itachi, but his mindset was certainly not as mature as Itachi's.
Sasuke had always been an immature child, drifting about without any goal. It could even be said that most of his life had been spent amid lies and deception.
This was a different world, and there were different choices here as well.
Sasuke's body had been modified, and he had also received Six Paths Realm chakra. Those factors gave him a high compatibility with the Ōtsutsuki Bloodline.
They first fitted Sasuke with an arm. That was crucial; lacking an arm greatly affected combat strength. Whether in coordination or combat ability, he would be weaker than an ordinary person.
Then came the injection of the improved bloodline genes.
At present, Kimimaro was the only one in all of Konoha who had undergone a full bloodline transformation. After so much time had passed, the various clans had already diverged greatly from the Ōtsutsuki Bloodline.
Blindly pursuing atavism was not necessarily the best course, but for Sasuke as he was now, if he wanted to gain great power, he had to find a way through bloodline evolution.
Sasuke was no longer young. He had already passed the prime age for improving his strength, and after sealing the Ōtsutsuki with Naruto, he had slacked off for far too long.
If they had continued training and fighting without pause, Sasuke and Naruto might not have been unable to reach the level of Hashirama and Madara.
Nothing was more dangerous in training than complacency. Once one's drive was gone, one would only grow weaker