After you defeat the Chapter 2 boss, you'll get an Oksae. You can either give it to Maru Han in the market area in town, or Gerrard, who will be to your right after you beat the boss. They both give a costume, but you should give it to Maru Han in your first playthrough. A quest down the line requires an item called a shadow humor. If you gave the Oksae to Maru Han, you can simply go talk to him in the market to get it. If you give the Oksae to Gerrard, you must go through the entire first dungeon again to get the shadow humor. I didn't notice any negative effects from giving it to Maru Han, so it's pretty dumb you get punished for helping Gerrard so badly down the line. In your second playthrough you don't need to do the quest so you can give it to Gerrard then.