Go back to first town, assuming you've already got the waterway key(forest 1), go on the boat and ride it down. Open the door and go down the stairs. Interact with the statue and get back to town. Now you need at least 200%(Might be 100%, but was at 200%) of your corruption bar and go to the hobo house right of town. H-scene procs and he runs out of the house. Go back to the statue and he'll give you a rainbow stone. Back to boss and use the rainbow stone to create a bridge.
Edit: Just finished the game, missing a lot of h-scenes for the pc but here's the save at throne room. (change the name back to .rvdata2)