In a low voice, Lin Yun pushed open the small wooden house and came to an empty space in front of it.,The ten levels of martial arts, the first three cultivate skin, bones, and meridians. The middle three cultivate flesh, blood, and five internal organs. The last three connect tendons, transform bone, and change marrow, reaching the peak of the tenth level.,Next, the entire skeleton rattled, booming with a sound like thunder. For a hundred sounds it reverberated, each one furious, like the roar of a tiger.。