Yoriichi Type Zero

Yoriichi Type Zero is a Battle Doll constructed by Kotetsu's ancestors during the Sengoku Era. According to Kotetsu's father, it was based off of an actual person, that being Yoriichi Tsugikuni.

I've hunted for him high 'n' low; I've looked him in the eye.

I dream about the perfect way, tae make this devil die.

Come taste ma blade ya manky bear for gobblin' up ma leg!

I'll hunt ye then I'll skin ye, hang your noggin on a peg!

Mor'du, Mor'du

Mor'du, Mor'du!

You're ancient as the highlands and as unforgivin' too.

Mor'du, Mor'du

Mor'du, Mor'du!

Now the time has come for all of us tae slaughter you!

He's bigger than a Cuillin, killin' armies with his paws.

Mor'du is never happy till the blood runs from his jaws.

He murders in the mountains and he fights with ev'ry clan.

His teeth and jowls have ripped the hearts fae many a highland man.

Mor'du, Mor'du

Mor'du, Mor'du!

He's stolen lads and lassies and wee 'bonnie babies too'!

Mor'du, Mor'du

Mor'du, Mor'du!

Now the time has come for all of us tae slaughter you!

Through glen and bog and peat and fog we'll find your furry lair.

And then we'll lance you, make you dance- you bear that are nae mair.

We'll roast your rump, add haggis and neeps, and fry your blue blood black.

We'll mix a slice of thigh with spice and grill you on the rack.

Mor'du, Mor'du

Mor'du, Mor'du!

We'll bile yur heed wae dumplin' breed tae make an ursine stew.

Mor'du, Mor'du

Mor'du, Mor'du!

Now the time has come for all the clans tae slaughter you!

We'll make his hide 'a cozy chair', his head upon the wall.

We'll splash a dram of whiskey on his snout at every ball.

Tales will tell from glen to glen of how we slayed the beast.

And all will toast brave highland men at every royal feast.

Mor'du, Mor'du

Mor'du, Mor'du!

The legend spreads from fire tae fire, of the devil that we slew.

Mor'du, Mor'du

Mor'du, Mor'du!

Now the time has come for all the clans tae slaughter you!

Appearance
Yoriichi Type Zero's appearance largely resembles Yoriichi Tsugikuni, the person it was modeled after. It has six arms and hands that each hold a katana, due to the fact that two arms weren't enough to even come close at replicating Yoriichi's movements. It is also shown to be heavily damaged, with half of its face and one of its arms missing after being damaged by Muichiro Tokito in training.

Swordsmith Village Arc
After hearing the "secret weapon" mentioned by Mitsuri Kanroji, Tanjiro decides to look for it in the forest of the Swordsmith Village, only to find Kotetsu having a squabble against the Mist Hashira to prevent him from damaging Yoriichi Type Zero.

In the end, Muichiro obtained the key to activate the doll by force due to Kotetsu's inability to physically fight back against him. During the training, Muichiro broke the doll's left shoulder armor and one of its right arms. Afterwards, Kotetsu fixed it and began to train Tanjiro using the battle doll. Due to the intense training that Tanjiro has went through, he had awakened the ability to predict his enemy's movements by smelling them and can tell where his opponent would aim next.

After being cut by Tanjiro, the head from Yoriichi Type Zero tumbles down only to reveal a 300 year-old katana hidden within its body.

Abilities
Yoriichi Type Zero has 108 different movements based off of the person it was modelled after. Its power surpasses most humans, which is why it is used as a training dummy for Demon Slayers. However, as centuries passed on, it has vastly withered and eroded, making it likely far weaker than what it was capable of during the Sengoku Era.