On February 3rd through the 7th, Pocolon Dungeon held a contest to see which Shaman King characters should be added in a future collaboration event. The 18 characters in the event currently were excluded and 14 characters (plus a write-in) were recommended in the contest. Anyone could enter, but you were only allowed to vote once. This contest was separate from the popularity contest held on the official website.
Today on twitter, the official Pocolon Dungeon account tweeted the winner was Iron Maiden Jeanne (アイアンメイデン・ジャンヌ) and provided two drawings. The first image was drawn personally by Hiroyuki Takei. The second image was a sketch done by the Pocolon Dungeon artists on what the character could look like in game. Both images are shown below.
In addition to the poll, there was a separate Twitter contest for entrants to win the physical drawing by Hiroyuki Takei. The current Pocolon Dungeon Shaman King crossover event is scheduled to end on February 25th in Japan. Characters and items unlocked can still be used after the event has concluded. There has been no announcements on when a potential additional crossover event will occur, or if it will available in other languages of the game. Jezzy has a write-up on her Tumblr blog on how to play the free-to-play game internationally.