When you first enter the Swamp area, a small boulder will block your access to the majority of the map. You need to have Ponta with you, and the tanuki needs to be at least grown to his third stage. If he's any younger then he won't have the strength required to destroy the boulder.

Next, make sure that the time of day is morning or night. You'll find a red ogre child in the northwest corner of the map. The ogre is so hungry that he is mumbling to himself. Offer to help the little tike (option #2) and suddenly you'll hear a horrible sound!

The little ogre's stomach is grumbling and so he requests that you bring him 10 fish. Any 10 fish you happen to have in your basket will be fine. The ogre will be so happy to be replenished. He was traveling around and got so hungry that he couldn't move. The ogre is thankful for you help, even if you are a human, and gives you 3 Panacea Bait and 1 Legendary Bait for your trouble.

In the southeast corner of the map is a strange, sleeping wall! There appears to be some sort of cave behind him, but your pet can't wake the wall up in order to get by. Maybe the red ogre can help you out with this fellow?

Visit the red ogre again in the Swamp (morning or night only) and ask him for help with the sleeping wall. The three of you walk back to the Upper Waterfall to try and awaken the dozing obstacle. The ogre doesn't have much success either, but if you tickle the wall it will wake up!

At this point you'll have to play the Wall Tickling mini game. Tap the spots on the way to give it a little tickle, and if you earn enough points the wall will wake up.

The ogre explains that you want to get by, and the wall politely complies by moving out of the way. You will then escort the ogre child back to the Swamp.

Return to the Upper Waterfall. You'll find Ren hanging out near the base of the falls. He has done a lot of fishing in the area but has not found the River King yet. Ren is wondering where this large waterfall comes from. In order to find the source of the falls he would have to climb up, but he doesn't have any way to do so.

Keep walking past Ren and head towards the waterfall. Your pet asks if you want to go up there, and then mentions that you're going to need to get a Rope to climb up to the top.