Hello and welcome to my Purity Tonfa build guide!
First off, this is my first guide ever so please be patient with me and I promise you'll have great results!

That being said let's hop into the first part here!

Purity in Nioh 2 is a wonderful status! It lets you do a boatload of ki damage and get grapples off rapidly, what weapon other than tonfa could make such great use of this mechanic!! Tonfas excel in rapidly dishing out damage and ki damage - they also have a built-in combo grapple!

So the first thing we'll need to tackle in the build is getting the proper gear, Getting Purity Tonfas shouldn't be too difficult and if you're truly having trouble with it - well you could just Forge Pagoda Tonfas as they come pre-built with purity in them.
The sets I run are 6 Piece One-Eyed Dragon's Ambition+ for that sweet consecutive attacks bonus and melee attacks ki consumption reduction! I also run 7 Piece Izanagi's Grace, there's no singular thing I run this Grace for as each of it's bonuses are fairly perfect!
I'll write down the piece by piece - set by set list as well, for easy viewing.

Pure Tonfas - Izanagi's Grace
One-Eyed Dragon's Dual Swords

Any two ranged weapons with Izanagi's Grace on there, remember to put Damage Bonus (Agility) on there, as it's one of the few ranged bonuses that can affect your melee.

Trident Vajra Sword Helmet - Izanagi's Grace (for the increased attack after performing Purification)
One-Eyed Dragon's Cuirass, Gauntlets, Waistguard, Greaves.

Any two accessories with Izanagi's Grace on them, and one of the accessories needs -1 Set Requirements reduction, so you can get the 6p + 7p set bonuses. Let's not forget about the Purity Accumulation + Melee damage vs purified targets, as every target we'll be hitting will get purified usually pretty easily.

I tend to put Active Skill damage and ki damage on my gear, along with the requisite singular Faster Winded Recovery and Tenacity (DoT). Running speed, Life, Attack, and -damage taken are all lovely as well!

Let's get into skills!
There's a couple of super easy to get into and easy to use combos for the tonfa's I recommend.
First off I recommend trying to find a Mystic Dyad (Tonfas) because both Kannagi and Apocalypse are phenomenal!
When using Tonfa's in the high stance, Demon Dance: Heaven is a great lead into a near-endless combo with Y>RB>XXX>RB>XXX etc.
It's a very strong combo that'll basically guarantee the death of any basic enemy/yokai.
If you're looking to spice that up a little I could recommend Y>X>RB>XXX∞

Pick up whichever perks you see fit in the skill trees, as it's basically user preference. This is a super easy build to work with after you get past the gear part of it.

The guardian spirit is also user preference, I say this because Phantom's Burst Counter is notoriously harder than brute's and feral's... If that doesn't bother you, I recommend Ho-Oh because calming breath is an astounding life-saver when combined with Ultimate Constitution, of course you also get that swiggity swoogity +10% melee damage against purified enemies ;)
Good luck slayers!

This is coming soon!