Sekiro

So i was at the merchant today after recently obtaining the mortal blade (this is my first playthrough) and i just couldnt understand why i would ever buy these. I then proceeded to try to beat the headless dude near the monk place in that dark cave (died a lot) and after failing and seeing that i once again lost all of my sen it dawned on me... i could buy the purses, fight bosses, and never lose sen...maxium facepalmHas this been in all souls games? Have i completely missed this mechanic in years of souls games?

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