An American Weeb Gets Sent to 13th Century Poland and Think's he's in an Isekai
The tale you are about to read revolves around the lazy, self-absorbed, and somewhat deluded mind of Brendan Flannagan - a black 15 year old from Southern California who enjoys watching anime (mostly Isekai like Konosuba), reading manga (but only long series like one piece because he doesn't want to grind through hundreds of episodes), and always keeps a spare bottle of lotion by his computer for purposes that are easily predictable (his favorite characters are women with large butts, if that helps you at all).
The story could start off in a multitude of ways: either Brendan can be seen at school, getting into arguments on My Anime List's casual discussion board while in study hall, or, we can start off with a certain individual who is the catalyst for the entire web novel that's about to be created: an evil scientist's cat named Pluto.
With a name that is reminiscent of the former planet, Pluto the cat is just as crazy as her owner, Dr. Time, who enjoys spending his free time drinking coffee at Starbucks and inventing new devices that could destroy the planet ten times over (meaning, he could kill the entire world's population in a day, repopulate it in just a few weeks, and then kill everyone the next day if he so desired). But, because he was rather crazy, he decided to keep those destructive devices hidden, because he thought Pluto would be mad if the owners of all of her feline friends suddenly died a gruesome death. And, Dr. Time was also very frugal (for no plausible reason, since he invented a way to perfectly counterfeit any type of currency). So, because of his modest spending, he lived in a one story home (with a basement turned into an evil lair) right next to our main protagonist - Brendan Flannagan.
I would like to call him a hero, because he's the main character, but I'm not sure if he'll ever become one - so let's hold back on calling Brendan a hero for now, and wait until he actually proves something. So, instead of starting this paragraph with: our hero did yada yada yada, I'm going to begin it with this (if you forget the rest of the words I just typed): our potential hero, Brendan Flannagan, had no idea that his neighbor was an evil scientist. And, not only did the large mustache, the blood curdling laugh, and the fact that he drove a truck with a 12 uranium missile silos on the bed not ring any alarms to Brendan - Dr. Time literally introduced himself to Brendan as:
"Dr. Time, evil scientist - it's nice to meet you lad. If you ever want to destroy the-"
"I don't care. I'm kind of busy, so we should talk later. Nice mustache though, and hey - that's a cool cat you've got."
So, while Dr. Time was flattered by the facial hair compliment, and the sincerity of attitude given towards his pet, he was also very off put by Brendan's lack of interest in the scientific profession, so Dr. Time never tried to talk about his evil plans with Brendan again. Which is a big reason as to why our protagonist was never worried about Dr. Time - he thought Time was just a normal neighbor that only talked too look cool in front of the local youth.
Now then, let's get back to the bigger issue at hand: Pluto the cat. Because on Wednesday the 6th (not that the day matters because this is fiction), she was extremely frazzled by a new gift given to her by Dr. Time. This gift made her dive bomb onto Dr. Time's head as he was working on his time machine, because she wanted to show her utmost admiration to her charitable owner. Which, ended up being a bad idea, because he yelled and whipped her off his head - sending her into a pole that snapped, and then fell onto the time machine, which then turned and misfired directly out of the small rectangular window which adorned the cement wall of the basement lair.
Brendan, who was watching Konosuba at the time, had his window open, because he had no fear of Dr. Time, and there was no reason for it to be closed (if he knew his neighbor was a mad scientist, he might have locked his window, and also his doors, and maybe begged his parents to move somewhere else). But, because he was dense and didn't listen to Dr. Time that fateful morning, Brendan Flannagan left his window open, which allowed the time blast to zing into his bedroom, bounce off a mirror, and then smack right into his temple, sending him back in time to 13th century Poland.
He landed with a loud thud and splat (the splat being caused by landing face first into cow poop). And after he got up with a groan, because the manure entered into his mouth and activated the worst taste buds possible, he quickly looked around and came to a stunning conclusion (which might have been bolstered by his recent watching of Konosuba - a show that includes a character who gets transported to another world): he was just sent to a new universe, and was fulfilling his dream of being the main character of an Isekai.
Sorry Brendan, you aren't the main character of an Isekai - you're actually the main character of my novel, and you haven't landed in a new universe - you've landed in the poop of a cow from 13th century Poland, where dukes and lords reign supreme, the poor struggle every day and then die abruptly, and everything gets burnt and rebuilt because of the constant state of warfare which is prompted by religious feuds, land feuds, and just family feuds (pun intended).