I'm quitting

You've worked hard all the way to level 400, wouldn't it be a shame to give up now? I know the ads are annoying, but didn't you say before that this game gives out a lot of gems? Let's calm down and take a break first. Don't waste all your previous effort on a sudden impulse!

This game is so annoying.

Did the hidden quest go up to level 400? When I accepted the quest, the final reward was only up to level 300, and I deleted it after claiming it.

I only have quests up to 300, how do I get to 400?

After I passed level 200, a hidden quest for 400 appeared! So it looks like this part is random too!

I've completed 300 hidden quests.