Oh my god! it's the flash's pace, plus he just discovered he was an assassin and already mastered the skills and got no problem killing... better see some tits though.
In the "assassin isekai" genre, nothing beat "Power in the shadows", also called: "When you take the chuunibyou to a new level". I hope it will get a manga adaptation.
I don't really like ironic descriptions like these, it somehow feels like they're looking down on me for liking isekai. I don't know maybe i'm just not understanding the joke right.
Isekai is not inherently bad. There are tons of good isekai when the author actually puts effort in - Faraway Paladin, Youjo Senki, Konosuba, and so on. The only problem is when the author doesn't even try. One chapter in and this series has already hit nearly every cliche in the book.