Cleared 2 Heroes with a stone spent, which was used on 1st floor. I could only stall for about 3 or 4 turns before I was killed, despite that I killed the Light Devil on my 1st turn :/
After that it was pretty safe, although I didn't think Knights' HP would be that low, causing me to kill them in one AoE blow and entered Vampire Lord's floor with only half of my health and some of my skills not yet stored...good thing their turn number was 223 =.=
Then the 2 Heroes, although it took a long while, but once Highlander died, it's a breeze dealing with Berserker.
Now my Wood team is completed, doing the 2nd run now, hopefully I can get Berserker in one go...
EDIT:
Got Berserker as well, and no stone spent this time, now my Water team is completed too ^_^