Ah, so you want to write a story following... Issei, from Highschool Dxd?

Mhm.

Yeah.

Okay.

You want to write a story about Issei not being a pervert, being the orphaned son of a dragon and a god, being part angel, and having more abilities than you can fit on your bio chapter?

Um, yeah, that's not even Highschool DxD anymore. That's like... a completely different story. At that point, you might as well write your own original story.

An AU story is generally the original story with one basic change that changes everything by proxy.

Underfell, for example. It's Undertale, but all the good characters are bad and all the bad characters are good. That, in turn, would change the entire development of the story. That's the example of a good AU (although I don't care much for Undertale AUs).

However....

You get a lot of fanfictions that love to change things in the story because... why not?

For example, in the disturbingly realistic DxD AU I gave, in most stories, Issei would still *almost* die to Raynare.

It doesn't matter if he's not perverted and wouldn't be in the situation! It doesn't matter if he should've probably awakened at an earlier point in his life! Nope, because putting Issei in Rias's Peerage means that you can lazily follow the already boring plot of DxD!

God, this is one of the most stupid things fanfic writers do. 

Why?

Because it's convenient!

UGH.

...

Okay.

In slightly more seriousness, an AU story has so much potential to be fun and cool that it really annoys me when they're bad. All you have to do is make EITHER a believable change and watch as it naturally changes the world, OR introduce the changes into the story naturally.

But nope!

Just throw everything at your readers and expect them to give absolute devotion to a book that you don't have any decent ideas for! Sure, that'll make you succeed!

Just... ugh.

...

I just read a Black Clover fanfiction that is basically an AU. There's a Demon King, and an Angel King, and the Wizard King isn't Julius Novachrono, and the main character is basically God x 100 because he's the last Nephilim to exist and—

It's a lot. It's actually way too much to be enjoyable. All of that that I mentioned and all of the context that it brings to the story is all introduced before chapter three. CHAPTER THREE.

It feels like someone thought about a lot of intriguing ideas but didn't care to polish them before writing and uploading. 

And it's not like I hate any of those ideas specifically, I just think the story would be 100 times better if 1) we actually knew anything about the main character beyond an overpowered set of abilities and 2) the story was willing to slow down and introduce new concepts slower.

But it doesn't.

And that story has over 400K reads.

Yeah... that's how you do well on Wattpad boys. Don't think, just write overpowered garbage without motivations for your main characters.

Ugh.