I remember several years ago, reading something on Fanfiction.net, that was structurally indistinguishable from an Isekai Light Novel (I think it was written when they were starting to get popular, but before they really took off), but it involved a WH40k Black Templar getting teleported to fuckin Azeroth from World of Warcraft.

And the main, or really the entire joke of the work really was largely that the entire world around this dude treating him as if he was some kind of weird Isekai protagonist goon who got given superpowers in another dimension; and people trying to like bribe, flatter, and seduce him on that basis into doing what they want him to do. But actually no he is just a mentally broken & severely brainwashed living murder-machine with barely any personality, and is probably going to try to kill the "Good Guys" too, when doing so becomes more convenient. The joke admittedly eventually collapsed, on account of going on for too long to really keep hitting right, and also because the author themselves eventually descended into Matt-Wardian Marine Wankery; but it was mildly amusing for like 5 chapters.