Castle Level 20 are you kidding me? Realistically, it takes more time to do the lvl 13 quest then it does to do the initial lvl 11 quest, even though the face value numbers and rewards suggest otherwise. That's cause of scaling. It takes 4 to 7 days to reach lvl 11, 6 to 10 days to reach 13, and anywhere from 2 weeks to a month to reach lvl 20, depending on how you use speedups, gather resources, and how aggressively you fight. Yet, the exp and points values don't scale to the same level. The level 11 quest has the best time to point ratio, with the lvl 13 being a smaller reward, with less exp, but the lvl 20 quest is horribly behind. Scaled up, it should've been a 700 exp and 8000 point quest, and lvl 13 should've been a 400 exp and 4000 point quest. All in all, even the level 13 quest isn't really worth the time, and lvl 20 definitely not. But at least lvl 13 is casually achievable in the time limit, lvl 20 requires a serious grind.