Animes watching their own universe

Chapter 26: Demon Slayer -- Tanjiro's Journal, Part 1--

"Okay everyone we are ready to start the next Demon Slayer viewing," said Mira.

"So we will be seeing Tanjiro's training in this one correct," asked Nezu.

"Yes, that's right. This will also be a two part viewing as well," said Mira.

"How long was your training," asked Izuku.

"It took me about a year of training to be ready for the selection exam," said Tanjiro.

"Well I for one am ready to see this training so shall we get started," said Chifuyu.

"Well then let's get to it," said Mira.

[--Demon Slayer: Tanjiro's Journal, Part 1--
"There are a few hundred members...of the Demon Slayer corps. The organization isn't officially recognized by the government. But it has existed since day of old and still hunts demons today. However, the identity of the leader of the Demon Slayer corps...is shrouded in mystery. Demons. Staple food: humans. They kill humans and eat them. It is unclear when or where they first appeared. They have impressive physical abilities and their wounds heal quickly. They can reconnect severed flesh and grow new limbs. Some demons can change form. Others possess strange powers. The only ways to kill them are by exposing them to sunlight or by cutting off their heads with a special sword."]

"What kind of strange powers and is there a group that actually know the leader," asked Koro-Sensei.

"The powers talked about are called blood demon arts and yes the Hashira are the ones that know who the leader is and his location," said Giyu.

["The Demon Slayer corps fights demons face-to-face. They are human, so their wounds heal slowly and lost limbs do not return. None the less, they fight demons in order to protect ordinary people. I am a trainer. Just like it sounds. I train swordsman. There are many trainers. In different places, they use various training methods. In order to join the Demon Slayer corps, you must survive the final selection at Mount Fujikasane. I decide whether you may attempt final selection," said Urokodaki.
'Starting today, I have decided to write this journal for Nezuko. Again today, I descended the mountain. I train as hard as I can so I won't die during final selection. I go down the mountain repeatedly, day after day. I've become quite good at avoiding traps. I'm growing stronger at picking up scents,' thought Tanjiro.]

"Geez, that had to be tiring," said Suga.

"It doesn't look to bad right now," said Denki.

"There has to be more to it," said Dabi.

['But the traps are getting much deadlier. It's like he really wants to kill me. Today, I went down the mountain with a katana. It really gets in the way...so carrying it got me caught in a lot of traps. Today, I practiced swinging the sword. I say "today," but lately I do this every day. After descending the mountains, I swing the sword so much I feel like my arms might fall off,' thought Tanjiro.
"...713...714...715...716...," said Tanjiro.
'The first thing he taught me was that a katana breaks easily. It's strong against force lengthwise but weak against force from the side. With a katana...you must attack straight ahead. When you swing a katana...the direction of the blade and the direction of the force you apply must be exactly the same. Furthermore...if you damage the sword, he'll damage...,' thought Tanjiro.
"...you!" said Urokodaki.
'In other words. if I break it...he'll break my bones. His threats are cold...like the mountain,' thought Tanjiro.]

"And there's the twist," said Dabi.

"How many times did you have to swing that practice sword each day," asked Sanzu.