Kusanagi Shiyū (志勇 草薙 Shiyū Kusanagi) is a member of the Japanese Self-Defense Force who is telepathically linked to the plants and animals of the Earth, and thus strongly resents humanity's pollution and destruction of the natural world. Although his punch carries the force of an earthquake and one of Dragons of Earth.
He meets Yuzuriha (and is the first man she ever met who can see Inuki) and develops an affection for her; although she falls in love with him, his intentions appear to remain unromantic. He frequently rescues Yuzuriha from death at the hands of other Dragons of Earth and, indeed in the anime, threatens Fūma and ultimately switches sides; as a result he is attacked and grievously wounded by Nataku and Arashi, the latter having also defected to the other side.
In the manga, he has, at the very least, expressed personal opinions that run contrary to the goals of the Dragons of Earth—specifically that life is sacred and should never, under any circumstances, be willfully destroyed. He also seems to think that conflicts between nature and humanity should be resolved with as little harm to either as possible.
In the movie, he does not show these pacifist qualities and instead actively attacks the Dragons of Heaven without hesitation and is a very violent character. Additionally, his relationship with Yuzuriha Nekoi does not exist in the movie.
Later on in the movie he was killed by Fūma, but he survives in the anime TV series.
Kusanagi appears twice in Tsubasa: as a player paired up with Nekoi Yuzuriha in Edonis Country and a fighter of the City Hall faction in Tokyo.