here is more on the hanzou part translated by Yagami1211 at NF
As I child I was scared so I stopped breathing with my mouth to prevent poisoning my surrounding.
Mifune : So why didn't you remove your mask ?
Hanzou : Because there is a risk. My mask is there to prevent me from breathing my own poison.
Mifune : ?
Hanzou : Think about it, if someone slash my inner poison bag, the poison would exit my body and there is a possibility that I would breath it.
If I breath all the poison, it would override my poison resistance and I would be render unable to move, creathig an opening.
And I can't allow this to happen. So I can fight people like you
Mifune : People and swords are alike. But now it's ... over for me. Profound Sadness !
Hanzou : Let me tell you something. Do you know when people die ?
Mifune : ?
Hanzou : When they lose their beliefs.
That's why you were a pain. People judge from outward apparence. You may be defeated but
that's not because you were too soft.
That's because you were afraid of my name. Because you swore to prtect your friends. Thoses friends you used as shields.
Mifune : *panting*
Hanzou : Now, hero, I will name you. Tell me when you die, Tell me your NAME !
Mifune : *breathing heavily*
Hanzou : Let me hear it !
Mifune : Don't ever lay a hand on my samurai comrades.
Hanzou : Here's a counter poison medecine.
Mifune : ?
Hanzou : They say you can't judge one's belief by looking at people. I realized during battle.
It's been a long time I saw someone like you. Today, I let you live. It's not like you were going to die immediatly after, though.
Hanzou uses counter poison medecine on Mifune.
Hanzou : From on now, will you die with your beliefs ? Or will you throw them and live ?
Back to present.
Mifune : I wanted to make sure but ... did you really threw you beliefs ?
Hanzou : You can't judge that by looking at me.
Mifune : !
Hanzou : I'm immortal all right, but there is a way to stop me. I already explained it to you Mifune.
Use the opening to seal me. If you don't do it, you will ...
Samurai : Master Mifune ! The poison is ...
Mifune : I'm ok. I have resistance against this poison. But from on now it will be different.
Everyone back off, with me. Prepare the seal.
Hanzou prepare to use his blade.
Mifune : Look around you.
Hanzou : Mifune, I entrust my beliefs to you. ( Hanzou stabs himself with his blade ).
Samurai : Seppuku ?
Hanzou : This poison is the real deal.
You can't breath this even if your have resistance against it, be careful.
Kabuto : My order fuuda tag is faiding. Suicide ? Then I just have to control all their moves myself one by one.
Hanzou shivers and crumbles.
Mifune : So you didn't threw you beliefs after all.
Multiple ninjas performs a seal on Hanzou.
Kabuto : What the ? The tag stopped working.
Mifune : "Hero" was the name you gave me. I was able to see your beliefs with my own eyes. Well done, Hanzou-dono.