wdym not there? WN just stops at the part where Hero of Destruction meets Allen, then suddenly skips to when he finishes building the IR for a sneak peek, no?
But storywise, WN skips all Demon Lords arc, which is the main storyline in Vol. 4. After that, it goes straight to that sneak peek chapter from WN. So in a sense, it’s already there in Vol. 4, but they included a whole new arc in between. That’s why I’m kinda looking forward to Vol. 5 since it should give us a completely new storyline.
It’s kinda understandable since in the WN, he wrote a spoiler chapter as chapter 1, and somehow the plot changed a lot afterward. That’s probably why he had to remove it so people wouldn’t get confused. (Maybe.)
As for the changes, yeah, he changed a lot of weird parts in the LN. Honestly, I kinda agree with this since his writing is kinda... bad and has a lot of disgusting and unnecessary parts that many people don’t like. But his overall ideas are interesting, so I can work with it.
You can read a translated version of the WN on Foxaholic. It covers the storyline up to LN Vol. 3, then continues from LN Vol. 4.