Ok so everyone know that mages have the hardest time doing the lvl 20 promo quest well not anymore because i will tell you how to do it the best way you can.
First thing you have to know is that you can be higher than lvl 20 when you do the quest. For example when i did it i was lvl 23 mage and you shadow will stay at lvl 19.
ok so lets get started these are the things you need a good cleric buff. vitality scoll t1 and t2, def scroll, aim scroll, magic def scroll and natural scroll. Well try to get as many buff you can
i recommend have all the armour and wep in the quick tool bar!!!!!!! very important.
So when you enter the dungeon take off all Armour and staff. DO NOT put the Armour/staff until the shadow is formed. Then kill all the monsters till the last 3 keblings skip them!!! . While following the blue light take off all the armour/staff again. Then when the shadow show up again put it on and kill the monsters before attacking the clone. Never let your health drop to a danger level. Do all this and you will finish it in the first go
Good Luck to you all and play it safe