After taking in the bleek state of Agata Forest, jump down the cliff. Amaterasu should land on a very slim path behind a waterfall. Behind it, there is a hidden tunnel that leads to Agata Forest's Guardian Sapling. Use Bloom to revive the Guardian Sapling, restoring life to the forest and dispelling the cursed zone. Open the chest in front of the enlivened Guardian Sapling to find the Devout Beads.
As Amaterasu leaves the Guardian Sapling's cave, she will be introduced to a mysterious man called Waka, who will be faced off against in what will be the toughest battle yet.
The easiest way to fight with Waka is to use the new Devout Beads as a Sub-Rosaries, and stay out of the water. If he throws his katana, Power Slash it to send it back and stun him. Snatch this chance to whip out at him.Cherry Bomb can also be used now to deal more damage to him, comparing to using Cherry Bomb on him when he is not stunned. Alternatively, the Devout Beads can be eqipped as Main, while Divine Retribution as Sub. This allows Amaterasu to land as many hits on Waka as possible, while granting her a Demon Fang as he attacks. Sub-Reflector Counterattack timing can also be practiced, and having a Sub-Reflector will protect Amaterasu from Waka's deadly combo chain. Repeat the strategy above until Waka is defeated.
After defeating Waka, Amaterasu is free to explore the Agata Forest and participate in any sidequests available.Look for the boy Kokari who is on a small island in the middle of the forest. Talk to him a few times until he starts crying, then give him a good headbutt to get him in the mood to fish. Draw a line from the end of his fishing reel to a fish to create a line that attaches to the fish. Pull the line in the opposite direction of the swimming fish to pull it in, then press the button when prompted to reel it up, then use a Power Slash to finish it off. After catching two fish, only one large fish will remain. Catch this Giant Salmon and it'll spit out the Ruins Key. Bring the Ruins Key to the entrance of the Tsuta Ruins at the south end of the forest and continue on to the next area.