In Douluo Su Yanyu has twin martial souls the first being the blue flame sword, the second being the blue Flame Dragon king (mutilate from the Fire Dragon King bloodline and the Water Dragon King bloodline).
The blue flame sword has the attributes of fire, ice, devouring, and purification. The souls that are fused with blue flame sword can evolve faster due to absorbing the devoured soul power.
Blue Flame Dragon King; is a fusion of the purified water dragon and the fire dragon bloodline by the blue flame and the blue flame itself and created a new pure dragon clan bloodline at the same level as the golden dragon king and the silver dragon king. The blue flame dragon king has the attributes of fire, ice , and power(although not as strong as the GDK but more powerful than most other dragons). The flame dragon king can create its own soul rings depending on Su Yanyu's spiritual power and physical power.
Su Yanyu can use both armed Haki and observation Haki in basic forms and the overlord depends on Su Yanyu's spiritual power.
Su Yanyu's bloodline after being purified by the blue flame is 7/9 dragon and 2/7 human