Although reluctant to believe you at first, you just manage to convince the shopkeeper that Shun Ziji is dead by your hand. It takes a good amount of convincing, and before the end of it the shopkeeper has to lock up and pours out a cup of wine. After pausing a moment, he pours another one out for you. You drink, and it's a local product, unremarkable but tasty enough in itself.
"You see, my sister saw Shun Ziji once. He was an assassin, aye, and one of reknown, but this was a few years ago. She was an associate, working for well, lets call her an evil woman. She was a moneylender and insurer, worked for boats, businesses and such. And sometimes she, well, she would play games with riders, changing the terms of the deal after the deal was made. Often after the original owner was no longer there to speak up."
He then takes another sip.
"It lasted basically a month. Something happened, and those people who she sent out, the ones who were a little less forward, a little more shady than my sister, well, they disappeared. Then the owner would get angry, and fearful, until she more or less lived inside her office, shouting orders, and almost refusing to come out and make appearances. And at the end, well, Shun Ziji walked in, opened her door, and killed her. Then he left. When the magistrates came to examine things, well, they found more than enough to make the whole matter clear, and since nobody actually knew anything about Shun Ziji, nothing came down upon them."
"So.. yes, I've heard of Shun Ziji, the assassin. I don't know anything about him, but since then I've been following rumors, and although I know he's not always one of the righteous, I know he once did me and my sister a great service, even if that wasn't his intention."
"And now.. well, I'm talking to his killer, and looking at his Black Blade. I'm sure you had to do what you had to do. I can examine that weapon for you.. and I can't say I'm not interested, even excited to do so, but I don't think I should do so for free. Give me one silver, and I'll examine it properly for you."