After reaching the 6th rank, one refines the organs to condense essence blood.

Essence blood is the quintessence of one's Blood Qi, the source of a martial artist's power, overwhelmingly potent. A single drop of essence blood can injure a 9th Rank.

Blood techniques rely on this blood to be performed, maximizing the power of essence blood.

One could say that blood techniques are the exclusive martial techniques of 6th-rank martial artists, impossible to practice without reaching this level.