As the title says I am looking for a well written realistic fanfic. I am looking for Realistic fanfic ,where mc learn things through hard work Non OP MC Mature Mc(yes, I know that maturity is hard to find in 11 years old) Try not to recommend this things Mc is a prodigy and he can kick Dumbledore's ass with on move No heir shit(it fucking sucks) No harem No bashing
Seconded! On the main topic. By the way, Fantastic Beast Series is good in case you haven't read the book yet.
Honestly your requirements are exactly the ones I have been looking for.... sadly I do not know one that fits all criterias. But Harry Potter and the prince of slytherin comes pretty close, though I bet you will shoot it down https://www.fanfiction.net/s/11191235/1/Harry-Potter-and-the-Prince-of-Slytherin
It has harem (but well managed), MC has a noble origin (and so it can fall in your dislike), and later mc will be overpowered (but not in the begin). BUT... maturity is almost MC second name. City of Sin. Another one that you may like is a record of a mortal’s journey through immortality, but it’s not finished.