The backstory wasn't too bad, it was just alot to handle at once. And well, it was alot in general. I feel like they could have shortened it down a nice amount.
It's espceally bad when you take the anime into consideration. After counting it out, it literally was 13/26 episodes of Backstory. Yes, half of the series was backstory. And since it said backstory starts about 10 episodes in...they basically spent a shitload of time explaining backstory till it ended.