The moment Sasuke had agreed on listening, Shishiou started to speak.
About Minamoto no Yorimasa, his master, his dearest master and the only he had ever accepted ( despite later on being at the hands of Ieyasu ), and how he frequently talked and thought about him. His master, who had committed seppuku and how Shishiou had been painfully lucky to be as tall as he is ( which was nothing compared to the other tachis ), because if he were only a tiny bit shorter, he would have taken the life of the man he loved the most.
He spoke of the following nine centuries, how he hadn’t been used to battle anymore, and how day after day were painfully slow and overall a torture because there were so many sword spirits that crossed paths with him, all who had a master & loved them & fought for them. He spoke of his origins, how he didn’t remember who was his “father”, who had smithed him, created him and gave him life. He spoke of his hidden jealousy towards his fellow comrades, of how many of them had “clans”, how many of them were brothers, swords of the same smither, and how it did nothing to Shishiou but make him feel horrible because he was alone, has always been, since Yorimasa died.
He spoke of how, despite his cheerful & charismatic personality, he was but a lonely sword; one that, as he had said, missed his master more than anything, and how the only other swords he was truly friends with were the very tantou that had took their master’s life, and Taira no Kiyomori’s swords, a member of the Taira clan who, despite the rivalry between clans, was one of Yorimasa’s dearest friends.
And he spoke, last but not least, between sobs and tears that were too embarrassing of Shishiou to let out, about how he worried, deeply and more than anything, he was a bother to his friends; because Shishiou, despite being a thousand years old, acted like a child, a very energetic one at that, and all of his friends acted so much more mature. He spoke of the last words Sharrkan had told him before he disappeared, of how he thought he was too demanding, too spoiled, and how much he worried that his friends just talked & stood him out of kindness. Because Shishiou was someone without nearly enough true friends, because every other sword had more important people, because maybe Shishiou’s personality was too strong for most people to deal with. Because Shishiou loved his friends more than anything, as he loved Yorimasa, and he was simply scared of being alone again, of not being able to make friendships and of spending his days without the amusement & distraction he needed -- because loneliness was cold and painful when all he could think of was the days he spent with his dead master.