There is quote from the opening, paraphrased: Isn't this like a lion throwing its cub off a cliff?
For all that those who see this series without context might find Kenshi an unbeatable Gary Stu, those who are familiar with the background will find it all the more hilarious no matter how overpowered he seems. Kenshi constantly compares himself to his half-brother and the 'sisters' he admires, and considers what he does as nothing special at all. As said elsewhere, this is the story of a baby MONSTER thrown out of his den full of MONSTERS to live among mere humans. The baby MONSTER then proceeds to MONSTER his way through his daily life, which is nowhere near as stressful as what he considers normal.
Isekai No Seikishi Monogatari offers great new twists to what should by now be a trite harem formula, and with an impressively high production quality. The plotline is likewise very well done, with some foreshadowed but still highly surprising curveballs and tells much over just 13 episodes. That each episode is also double-length compared to the typical anime episode makes this a great value.