Akuma vs Zaraki Kenpachi

Akuma (Street Fighter) and Kenpachi (Bleach) are teleported into another dimension, after hitting reality itself very hard. There, it is just themselves...until they find each other! Realizing that the person in front of them is very strong, it doesn't take long for the two of them to prepare to attack at one another.

• Their fight takes place in an empty, endless wasteland with nothing but these two on it.
• They won't go all-out from the start.
• They are at their first forms, at the beginning of the fight. Akuma can enter his Shin or Oni forms. Kenpachi can simiraly release his shikai or bankai.
• To enter their next form, the previous one must be not enough to defeat their opponent. So, if Akuma can't beat Zaraki, he can go Shin, if he still can't beat Zaraki, he then goes Oni. The same goes for Zaraki. First he releases his shikai, then his bankai.
• They fight merely for their own entertainment, but will go into an all-out berserk, if that's what it takes to take their enemy down. Apart from that, they are in character.

Who do you think would win if these two faced each other? Well-thought answers are welcome, with every vote.