"Um, Miss Tamayo... is there anything I need to help with for this experiment?"
Tanjuro stood in the middle of the laboratory, looking rather bewildered.
He did not even know where to put his hands.
Watching Xia Xi and Tamayo stare solemnly at the caged mice while scribbling and sketching in their notebooks.
Charcoal Seller grew even more nervous.
As far as he understood it.
He was just a rough fellow who made a living through physical labor.
Things like medicine and experiments.
He knew absolutely nothing about them.
So, when he heard that all these laboratory mice had been injected with his blood.
And saw that some had not only lost patches of fur but also developed strange, dark red marks...
The indescribable sense of absurdity in his heart grew even stronger.
His blood.
Really did contain something extraordinary...
Come to think of it, have Mr. Xia Xi and Mrs. Tamayo already found a solution?
Faced with Tanjuro's question, Tamayo did not answer immediately. Instead, she turned to look at Xia Xi beside her.
Only then did the Dawn Hashira explain casually, "This is the first generation of the [New Demon Slayer Mark] vaccine we've developed."
"Haven't you been very concerned about this?"
"Well, since you weren't out on a mission today, I called you over to see it for yourself."
At a moment with this sort of ceremonial significance.
Of course they had to invite the father of the source material for this batch of laboratory mice-Tanjuro Kamado.
So he could see with his own eyes how they survived this final trial.
And transformed into true Demon Slayer Mark Battle Rats.
Tanjuro: ...
Why does this sound like an inspection of weapons?
Tamayo beckoned Tanjuro over to a cage and pointed at the experimental subjects inside.
She began