Wonder how he dies

I'm translating a kung fu movie where the protagonist, having mastered the Shaolin Invincible Body technique, renders himself impervious to harm - his only weak spot is his anus. I'll give you a moment to savor that one. I've yet to actually see it*, so my imagination is just teeming with images. Take for instance this exchange:

- Mom said that after you've been immersed in the wine, the only part vulnerable is your anus.
- Do I have to walk like this from now on?

You'd think it would be the Greeks who'd go there first, but no. It was the Chinese.

* the movie is in Mandarin, and I have a - sort of - English script, so the process is inverted: first I translate the lines, and then try to match and adjust them to the video