Side Quest: Sukiyaki Party

After you've proven yourself in the Coliseum to the Grand Noah Queen, you'll be approached by Cerberus and Dullahan after you leave the throne room. Once you force them to stop talking over each other, talk to Cerberus; she'll ask for your help to track down over 40 missing Minotaurs.
 * 1) Head to the Grand Noah bar for information. Talk to the Red-haired man at the end of the bar.
 * 2) Go to Blacksmith where you'll find the only remaining Minotauros. She explain every Minotauros received an invitation to a Sukiyaki Party out in the middle of nowhere, but she was too busy to go. She gives you her invitation and off you go.
 * 3) Head west out of Grand Noah until you reach a tunnel entrance. Go through the tunnel and on the other side, you'll find a castle. Show your invitation to gain entrance.
 * 4) Go inside and fight your way to the boss room. On your way, you will first fight Sun Wukong as a warmup boss. When you reach the end, defeat the Cow Demon Queen and she'll send all the Minotaurs home. Cerberus will join your party officially and the quest will complete.

Optional steps to recruit Cow Demon Queen
Back in the tunnel near the exit to the castle is a lone Minotauros. Give her 10 Sukiyaki and she'll give you the Horn of Friendship. Show that to the Cow Demon Queen and she'll join your party. Two Sukiyaki can be found in pots close to the entrance of the castle. They can also be farmed as drops off the Minotaurs inside.