Rain Wheel randomly appears on the 3rd and 4th floors of Marukyu Striptease if the party visits the Midnight Channel on a rainy day. It does not have any special attack skills, but its normal attacks can be quite damaging due to its high Strength stat. After being defeated, it may drop the Zero Cloth material. Selling this at Daidara will unlock the Zero Kosode female armor, which has the second highest defense at the time and an Evade spell effect, but low base Evasion rate.
In Golden, Rain Wheel appears on floors 3, 4, 7 to 10 of the club. It may drop Lemon Quartz and/or Olive Stones for trade at Shiroku Pub.