Reward: Assassin's set (class 3 light armor) In the room you enter, you'll see a Hardlight block that can be wall-jumped up to.
Go to the boss area, drop down to the left like you did after beating him. Reward: Lightning Ball spell (class 2 magic) There will be 2 Hardlight blocks off the ledge to your right. It won't cover any secret areas that you can find the first time you enter an area, so this guide is for backtracking stuff only.
This will cover every treasure that you need to backtrack for, after you've picked up new brands.
