-( Story related, cannot be missed )-
Once you've revived the Guardian Sapling in Agata Forest, you will come across this strange man known as Waka. Though his motive is unclear when you first meet him, you must fight him to prove to him you are who you say you are (or who Issun says you are). His attacks are quite simple and won't overpower you. It would be simple to just use the rosaries you should have by this point and take him on from a distance, equipping the Reflector in your sub-weapon and defending when he comes in for a hit.