- Tekkai/Iron Mass (One Piece)
The user's muscles are so dense and bulky that that they can use purely that to cause physical attacks to bounce off of their muscles. Since the muscles are directly under one's skin, the bulk can be used to protect one's bones and innards. By bulking the muscles at point of contact, the user can even bounce the attack back.
- Areas with less muscle concentration may be less protected.
- Areas with no muscle concentration are not protected.
- Does not protect the outer skin, so scratches and flays on that is still possible.
- If attacks gets into body, then muscles cannot protect.
- May require user to consciously bulk up muscles to block attacks.
- Muscles are still part of one's flesh body, and are vulnerable to damages not of pure brute force (burning, freezing and electrifying).
- Gyanza Rujike (Black Cat)
- Akisame Kōetsuji (Kenichi The Mightiest Disciple)
- Balke (Luger Code 1951); via his werewolf form
- Tekkai users (One Piece)
- Monkey D. Luffy (One Piece); via Gear Fourth
- Pokémon that can use "Bulk Up" (Pokémon)
- Younger Toguro (Yu Yu Hakusho)
- Energy Steroid (One Piece)