Demon of Song

This is a large frog enemy and the only vulnerable part of it is its face. If you're a ranged character, you just need to approach it to force it to reveal its face and arms then quickly move back to avoid its flailing arms. If you attack it from a distance, it will dash towards you which is really hard to avoid and will cause tremendous damage. Aside from its normal flail attack, it will stand up and will attempt to crush you. For melee characters, you need to time your attack right after the boss misses its melee attack. This boss is slow and its attack patterns are quite predictable so this battle isn't that hard overall.

After defeating the Demon, continue along the next path. Continue past the passage and head to the tower. You'll find another bonfire inside so light it up and rest as necessary. The door at the top of the tower is locked so ignore it for now. Leave the tower and go through the next path. Open the door and ride the large lift inside. Once you reached the bottom, continue forth to reach the next area.