I am with you.It is a great spell, but going BACK to sunken city is just plain annoying.I give you advice: Beat it before you get to mooshu, or beat it before you face this oni: The Plague Oni. You get the quest after sunken city to beat him.I beat the first part of the quest after the Plague oni.The quest is so annoying for such a good healing spell.The only thing i don't like about the spell is that it eats up all your pips. :( I haven't used the actual spell yet, i have it in my deck( i am in the lvl40s so i have a big spell deck ). William Shadowfriend, Lvl43 Theurgist Either Master Theurgist, Master Of Karate and Friendship, or Oni Slayer.
There are other times you will have to return to a certain quest or area just for a school spell. You are not the first to do this and will not be the last.