You have to finish Mooshu and the sequential worlds before it first. Then Professor Ambrose will send you to see Cyrus Drake. When Professor Drake is satisfied with your ability, he'll instruct you to go to Dragonspyre, where he'll be with further instructions.
Defeat all 4 oni's. War. Plague. Death. Jade. War oni is in crimson fields ( Must complete tasks in in hamestu village and tataki outpost?) Plague oni is in shirataki temple ( Must complete tasks in cave of solitude and kishibe village.) Death oni is in tree of life ( must complete tasks in ancient burial grounds and village of sorrow.) althrough i'd say tree of life is shorter then shirataki temple lol . When you complete all those tasks you get a task from a monk (forgot his name.) to defeat the jade oni!
War oni health : 2,000 and 1600 i do remember seeing that lol ( the pigs change into the oni's so dont leave when you defeat the pig cause you'll have to defeatt the oni right after it) fire then fire
Plague oni health : i think 2,200 and 1,800 ice then balance
Death oni health : Forgot, Somewhere around 2,500 and 1,950 death then death
Jade oni health: Haven't forgotten. 7,500 life ( you dont fight a pig before the jade oni, you just defeat the oni. Then someone gives you the dragonspyre key, you talk to merle ambrose, gotta defeat cyrus first (5,000 health myth) then You meet cyrus in the bastillica
first get past wizard city into krokotopia then get to marleybone then mooshu then dragonspyre then celestia this is the order of story line worlds
CORRECTION! You go wizard city then choose the course of krockotopia or grizzleheim. Choose grizzleheim and finish to wintertusk. OR.... go to krok and get to lvl 25. after lvl 25 you can choose to go to pigswick. OR finish krok go to marleybone then mooshu then dragonspyre then celestia. and celestia is where you should worry on how to get in. you MUST be a lvl 48. and you have to do a tower in marleybone but just because its in marleybone doesnt mean its easy. THERE ARE CHEATING BOSSES! you need like you and 3 lvl 60. but i soloed it and won ^_^ very easy for storm if you ask me.