Yes, The Empty Class is indeed a fan fiction. The first chapter itself starts out with the character making a character in 'Royal Road', which is the VRMMORPG game of The Legendary Moonlight Sculptor. Just because it changes later does disregard the fact that it had began as so. If the author had wished for it to be original, he would have done so in the first place.
Then please inform me when it is rewritten and what have you.
To answer the question of the previous inquirer as well, I had removed Phoenix Rising due to claims from users of it containing plagiarism (specifically: Mushoku Tensei -Isekai Ittara Honki Dasu-), which I detest. If you wish to read it, here it is. I have read that he is planning on rewriting the beginning chapters to fix this 'issue', but that is to be seen.
I'm not really sure what you meant, but what I'm trying to say is even though it starts out with the name Royal Road. Since the author didn't borrow lore or events from LMS, characters, places, and even made his own skill and job system. Later on he changes it to original by changing the game name from 'Royal Road' to 'Fantasy Online'.
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I actually wants to read because someone in the previous said that, haha.