Help!!

From the first time I started writing fanfictions, I always have a set program which is

1. look for a timeline of whatever anime it is

2. get a decent grasp of it then do whatever I want with this information

This is how I write without writers block

But now I'm facing an issue

There's no timeline for Highschool DXD...

I've only watched 2 out of 5 seasons and I've never read any of the light novels

So I'm stuck before I even got started

So now I have 2 options

1. get a basic grasp of key parts and fill in whatever I want

( advantage? there's none )

( disadvantage ? several, I may not have anything to write meaning delayed updates, I may write a bunch of shit which makes no sense and is completely wrong such as me not knowing what tier anyone is, I won't know if I miss anyone important, and if I do I may have to tap back to add them in)

2. go through the character profiles on the wiki page and create my own time line

( advantage? factual information, somewhat flowing story, fleshing out the characters, as this will be the longest volume yet )

( disadvantage? I have to create a fucking timeline!!!!!.....time consuming )

***

So I need some help