I don't think it's just that.
He worked his ass off to get where he is now, reaching even his old age so he spent his entire life on this. Then suddenly he discovers that the world he lives in is actually a fabricated world inside a story, he's just a written character, a SIDE character at that, so not really an important one. I challenge everyone to not feel angry after discovering your hard work doesn't exactly belong to you ╮(￣▽￣)╭
There are days where I have felt the same.
If I was in his shoes I wouldn't be angry, maybe highly disappointed, but if he knows the world is fabricated why does he still want to be emperor?
Exactly
I guess he thought that since all his efforts were useless, since is Vasser that decides the roles anyway, he might as well become emperor which is the highest position in this story, going from being no-one to being the someone.
I still can't believe Edwards mad just because he became younger,and he wants to be the emperor now? what a stupid request