Find any chests you could not open near the start of the act?
<span class='standouttext'>Spoiler : </span><span class='spoiler'>The first BF key is in a locked chest in the cell block you started in, with the key in the left spider cell in the arena. A second level 1 key is after getting past some skeletons chained to pillars, in case you missed the first one.</span>
