Let me do an honest review with strengths and weaknesses in this story.
Writing quality (4/5): grammatical errors appear here and there and words are repeated in the same sentence sometimes but in general it is good
Stability of updates (4/5): I can't say much but it seems to be good according to the history and update date, but some readers sometimes comment that the author has a history of dropped stories so 4/5 is enough note
Story Development (2/5): the story starts with yosuga no sora the MC has memories of his previous life and becomes a writer copying a story of it, then he receives the mysterious group chat app and other people from other world are invited like tsunade (naruto), yojima (fairy tail), kuroneko (oreimo) and gintoki (gintama) the MC never suspects anything of the semi-omnipotent app that can transport people to another world and sell powers in the store, the worst thing here is that the MC believes in "destiny", he believes that it is impossible not to follow the destiny of the original anime he is part of (he is the MC of yosuga no sora) so he doesn't even try to go against the incestuous romance with his sister, he simply follows the flow, he lies to himself saying he doesn’t want to get into a relationship but flirts with every girl he sees, he’s very hypocritical and in chapter 157 (where I dropped it) you see it clearly, you just need to read 156 and then 157.
character design (1.5 / 5): the author simply inserted female characters while thinking with the penis, more and more female characters appear and the MC flirts with all of them, even has sex with some of them without commitment, the female characters don't have much personality and fall in love with the MC without reason, simply because he is "charming", Sora (his little sister) for example is sticky and the only thing he talks to the MC is asking if he will leave her and where and with whom he was , it's just ridiculous, besides there being so many new girls included all the time that you even forget some of them, the MC's personality is also bad, similar to the typical villain of xianxia + harem protagonist who is taken by the flow, whenever he sees something incredible he covets, feels envious or says he doesn't feel envy because in the future he will be as strong or rich as that person, says he is not arrogant but believes that he can get a perfect score in a test while focusing on 3 others isas instead of the test itself, he believes that he is on the same level as a national athlete practicing swordsman being that he only trained 2 months while they do it for a lifetime.
but what broke the limit was in chapter 157, in chapter 156 he decides to enter into a relationship with one of the characters, but in chapter 157, when not even 24 hours have passed he takes the initiative to enter into a relationship with his sister !?
Okay, I understand that the title already says that, although not always a siscon enters into a relationship with the sister, but it was more or less predictable than in the case of him, but he ignores the feelings of Kato (the girl who confessed him in 156) and to relate to the sister in 157 as if it were nothing, and that just tells me that he is an incorrigible hypocritical scum.
world backgroung (3.5 / 5): the main world of MC is a union of several worlds with several characters from various anime / manga, which is interesting, but the author exaggerated and even put characters with abnormals there, also has little information about the characters which makes them simply names, and forgettable also due to the size of the harem
in conclusion it is a story that has good fights although they are few, interesting powers but I think it needed to be explored more mainly the magic of light and the chakra, but very bad in the romance, harem, randomness, and characters in general mainly with regard to personality, including the MC.
