The fae prince is a completely waste of time for those wishing to continue this game. Despite proper strategy and planning, unless you wish to devote worthless hours to grinding - it isn't worth it. The fae prince will just spam cyclone and summon bramble, he will attack multiple times in a row and even with Regen on everyone, it;s useless. Ash trying to reduce his MP is also a waste of time as it's MP pool is insanely high. 

If you want a challenge, go forward with this game and keep trying. Otherwise, you'll  just be pulling at your own hair in frustration by the hours wasted on grinding levels to just beat a fairy prince.