Nature

Ryuzaki Ikuo and Danno Tatsuya the twin dragons of the Ouroboros decided to walk the earth on both paths the dark and light- underworld and public respectively. However, the world is not so black and white, as shown by the pit black underbelly of the police force, and the seemingly kind gestures of the Yakuza.

Ikuo was not as bubbly as he seemed and definitely not as clueless as he occasionally portrays himself. Beneath his easygoing and innocent facade, Ikuo had a hardened side to him, a backbone of steel and a vicious bite when it comes to things that threaten the things he protects. He was willing to be wolf in sheep's clothing in a manner of speech. Despite this darker side, he indeed posses the qualities that made him the conventional kind person, he was not openly antagonistic and had a truly altruistic and righteous nature. Thus Ikuo was the one to walk in the light.

On the other hand, Danno was inclined to be cheesier and running more intimately with the dark side. Outright portraying the character of a criminal, he handled his role well, like a dark cloak that embraced him in the darkness of the night. However, there are stars that appear in the night, illuminating the place even more with the contrast. Danno had a kind heart, his cruel ways- blunt letdowns, troubling shenanigans were the exposure of his true nature. Once you knew him personally, these actions did not belie his kind nature but in fact accentuated that with the fact that he was very much entrenched in the cynical reality of the world. As such, Danno appointed himself to be the black horse of the underworld.

Thus, the two dragons- complementing each other's contradictory personality was linked through their inherently kind nature, seeking for revenge against the murder of their beloved sensei. With their resolve they were united, with their fate they were intertwined, with their personalities they were infinitely compatible.

Like a puzzle piece or the tail of the dragon they fit together perfectly as one.