-I always put 5 stars since it is not easy to create a story, be it good or bad, I only put less when they put genres that do not appear in the synopsis or when they do not warn and then you read things that you do not want and did not expect.
-It is a good start for the story, you just have to correct grammar mistakes, there are times when the name is not correct, "he and she", they change places.
- If you only correct and put the names correctly it would be more understandable for the rest, since I can read normal, because I am used to reading worse grammar, but history always compensates it.
- If you have time, look for a proofreader or use grammar, which is free, but if your story is good.
- good start of the harem with "grayfia".
- Then you can continue with yasaka, since it is a yokai, then tiamat, later "gabriel", then laviana reni, and more mature girls that are not used much, I like how you changed to koneko, and not to mention that can have a both kittens xD.
-and finally I liked that you did not do the same as many authors who help Issei, since he is his brother, those "fanfic" whether yuri, harem or no harem, they always do it and the story gets boring, it's Better to let him go on his way, in the end he has the plot armor so that he survives (just match Issei with Irina or Asia, don't give him a harem, otherwise you would also have to be putting another "pov" from his brother) , and I can only say that you keep more chapters and improve your grammar.