Dolgoterov body hardness

Dolgoterov was born with great power and had dominated the underworld of boxing. His body was as tough as steel and he practiced Ancient Yoga to combine hardness with flexibility.

However, the area he excelled in the most was the Joint-locking techniques he obtained by coincidence in China. After successfully practising it, Dolgoterov became the most fearsome close combat fighter with the nickname ‘Body Crusher’ and joined the ranks of the other S-level hitmen of the underworld.

http://volarenovels.com/the-nine-cauldrons/tnc-chapter-7/