Humanity: Multiversal Adventure

Ronan is an ordinary human who, after an unfortunate accident that ends his life, finds himself reincarnated in the universe of DXD as a simple human. Although he didn't know which world he was in, from a young age, he trains. At the age of 14, he awakens a system called the Travel System. Its sole function is to allow him to travel between worlds, where he can choose the place and time.
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[This is a story primarily for personal satisfaction and to enhance my writing by letting my imagination soar with little restriction.]
[The fanfic contains all kinds of dark themes, so discretion is advised. Relationships will be as in H (there might be romance), They have already been warned, so reviews that are solely about that will be removed]
[I am not the author of DXD, nor of any of the works presented in this stories. I only own my OCs. I'm not a native English speaker, so I use the famous ChatGPT to translate everything so please don't bother with Gramatiga if you don't have a solution]
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confirmed there are:
incecto, relatively large haren, romance although sure cliché since I don't know how to write, human all the time, R18 like Hentai although I have to learn, Milf, Mc Dominant (although I didn't write R18 chapters, the mc will always be dominant), characters from other franchises in DxD, (example afrodita from dxd looks like the one from record of ragnarok afrodita).

there might be but not confirmed:
loli but probably legal (e.g. Yue or Tatsumaki), Netori (i.e. stealing wives of others), Yuri (but outside the harem, i.e. friends who are lesbians but not dating the mc), sexual friends (not in the harem but get along well, I made this one in case I wanted to R18 with a character who is not in the harem and is from a world that the mc traveled to).

you will never find: NTR to the MC, Yuri in the harem, Japanese beta protagonist.