I'm not sure specifically what the'sama sama letter day story' is about as it's not a widely known common story. It could be a very personal or a story from a specific local or cultural context.
The Kaguya-sama manga is indeed finished. It ended after a successful run, leaving fans with memories of an engaging and enjoyable story. The final chapters tied up loose ends and delivered a conclusive ending.
Yes. The Kaguya-sama manga has reached its conclusion. It provided a satisfying ending for fans. The creator wrapped up the plotlines and characters' arcs neatly.
The 'tensei shitara ken deshita web novel' could potentially be about a unique fantasy story. Maybe it tells the story of a person who is reincarnated as a sword. This sword might have special powers or abilities. It could be on a journey to discover its purpose, meet various characters, and be involved in different quests in a fantastical world. There could be elements of magic, different races, and complex relationships within the story.
Well, without having read the 'jitsu wa ore saikyou deshita novel', it could be about a journey of self - discovery where the protagonist realizes their own hidden power. It might involve battles, either physical or mental, against various opponents and through these experiences, comes to the conclusion that they are actually the strongest.
I'm not sure exactly as I haven't read it. But 'isekai' usually means another world in Japanese light novels. It might be about a character who enters another world after some sort of action (represented by 'kachikomi kaketara').