Hayate

Hayate is a character that first appeared in Dead or Alive 3, despite his appearance as his alter ego Ein from Dead or Alive 2. He is the leader of the Mugen Tenshin Clan and is Kasumi's big brother and Ayane's half sister. He and Ayane makes a great connection and chemistry with eachother despite the fact they are half siblings. He is also the friend of Ryu Hayabusa but unlike him, Hayate is a reserved ninja.

Before Dead or Alive
Hayate was a ninja in the Mugen Tenshin ninja clan. He had a happy childhood with both his sister Kasumi and half-sister and cousin Ayane, who both love him very much. He is also a good friend of Ryu Hayabusa. One day, the expelled ninja Raidou, who is also Ayane's father, attacks the Mugen Tenshin village in an attempt to steal the Torn Sky Blast ninpō attack. Raidou defeated Ayane and then challenged Hayate to single combat. Hayate was overcome by Raidou's superior fighting ability, and had the Torn Sky Blast stolen from him in the process. As both of their ninpō attacks collided, the resulting explosion threw Hayate into a tree, cracking his spine and sending him into a coma. Kasumi looks after him while he is in a coma, but she soon departs the village, taking Hayate's sword with her (thus deeming her a traitor) in order to seek revenge against the one who harmed her beloved brother.

Dead or Alive
During the first Dead or Alive tournament, Hayate had been captured by DOATEC and made into a superhuman. This was done by mind control and some genetic engineering via Project Epsilon. The leader of DOATEC at that time was Fame Douglas, whose organization wanted to create an ultimate superhuman. Hayate was not a participant in Dead or Alive, but he had a major role in the motives of some of the others.

Dead or Alive 2
After the first tournament and the end of Project Epsilon, Hayate was left in the Black Forest of Germany and was in a state of temporary memory loss. He could not remember his name and went by the name of Ein (which means "one" in German). He studied karate under Hitomi's father, and soon mastered it. After that, he joined the second DOA tournament to find answers to his lost past. He was defeated by Ryu Hayabusa, who would later win the second tournament by killing the evil Tengu. After his defeat, Hayate's memories slowly began to return to him. Before they did, however, he faced both Kasumi and Ayane.

Dead or Alive 3
Hayate returns in Dead Or Alive 3 with his memory regained and as leader of the Mugen Tenshin style. His reason for joining the tournament this time is to defeat DOATEC's next superhuman creation Omega, who was Ayane's foster father until he was turned to evil. Some of his new moves are similar to Kasumi's; this was done on purpose to show their connection with the same fighting style and the same ninja village where they came from. He also knows some old moves from his karate experience. Although he felt it was his duty to defeat Genra as leader of the shinobi, Hayate was beaten by Ayane. Ayane proceeded to the final round and killed her foster father Genra, citing that it was a personal affair.

Dead or Alive 4
With Genra out of the way, Hayate now goes on a quest for revenge against DOATEC for what they did to him. He joins forces with Ayane, his half sister, and Ryu Hayabusa, a friend of his, to take down the corrupt organization, as well as their new creation, Alpha-152 (a clone of Kasumi). During the fighting in DOATEC's Tritower complex Hayate comes across La Mariposa. There's more to this female wrestler than it seems as she appears to have some info on Project Epsilon and may have been responsible for Hayate's memory loss.

Meanwhile Hitomi is looking for Hayate (or rather Ein) to help her rebuild her father's dojo. Hayate agrees to come with Hitomi if she can defeat him in combat.

At the end of DOA4, Hayate and his ninja comrades destroy the Tritower complex and escapes the building as it burns to the ground, while Kasumi battles Alpha-152. In his CG ending Hayate actually kills few of DOATEC's army, & then he is seen jumping from different cars and vans and uses his bow to set the DOATEC zeppelin on fire. It is unclear, however, if this is the last of DOATEC after this major blow to their organization.

Personality
Hayate has a powerful sense of duty when it comes to his role as the leader of his clan. He is so devoted to the clan's rules and traditions that he hunts down his own sister, with much reluctance. He also feels that it is his duty as the clan leader to defeat Genra in Dead or Alive 3.

Hayate was close with his sister Kasumi throughout their childhood, and thus does not attempt to kill or capture her over the course of Dead or Alive 3. He has also developed a special bond with his half-sister, Ayane. He has always played the role of her protector, even though she is an illegitimate member of the family.

Movie Appearance
Hayate is portrayed by Collin Chou in DOA: Dead or Alive. In the movie, he is simply captured by DOATEC after winning that year's DOA competition rather than being captured by DOATEC in his home village. Also, he is simply meant to test Donovan's newest invention rather than being tested on Project Epsilon. He is also the reason for Kasumi's entrance in the tournament like in DOA1.

Hayate and Ayane are shown as lovers rather than half-siblings. The fighting style he used was Eagle Claw.

Hayate
Hayate can best be described as a merge between the play-styles of Hitomi and Kasumi. He now features a somersault kick similar to his ninja counterparts (Maizuru), however his throws have been slightly reduced in power. Many of his attacks have extremely fast start-up and inflict decent amounts of damage. Despite all this, it should be noted that one move in particular, "Raijin", is known as the hardest command throw in the game in terms of execution. It should also be noted that "Raijin" is not the most powerful throw in the game, despite its complexity, but can be very damaging. He is consistently listed as one of the best characters in the game, making him at least top-tier and is a known favorite amongst the ninja characters of the series. He is an extremely popular character and is often used in the online mode.