<Li> Wo Fat (Mark Dacascos) was the principal antagonist and nemesis of Steve McGarrett . He is well known in the criminal world for his ruthlessness and ability to wriggle his way around the law . In the 100th episode, he kidnaps McGarrett and tortures him with a heated cattle rod and truth serum . After a bitter fight to the death, McGarrett kills him with a bullet to the head . </Li> <Li> Victor and Anton Hesse (James Marsters and Norman Reedus) are brothers and criminals heavily involved in the illegal arms trafficking trade . During his days as a SEAL, McGarrett was part of a task force which had been investigating and tracking the Hesse brothers for several years . He and his buddy Freddie Hart were sent into North Korea on a classified operation to kidnap Anton Hesse but Hart was killed and Anton was eventually killed when the convoy he and McGarrett were being transported in was attacked . In the pilot, McGarrett personally shoots Victor Hesse but his body was never found . Victor later resurfaces and is eventually caught and sent to prison where he is killed by Wo Fat who was posing as a corrections officer . </Li> <Li> Gabriel Waincroft (Christopher Sean) is the younger brother of Malia Waincroft, the late wife of Chin Ho Kelly . As an adolescent he repeatedly got into trouble with the law and Malia went to Chin, then her boyfriend, for help in setting him straight . Gabriel was initiated into a gang after killing Chin's father and rose through the ranks of the (fictional) Culiacan cartel based in Sinaloa, Mexico . With Wo Fat's death, Waincroft is now the team's primary antagonist . He has been described as daring and ambitious, particularly after he had his men attempt to assassinate the heads of three different criminal syndicates during a high - profile boxing match (the attempt was discreetly foiled by Five - 0), in the episode "Ka Makau kaa kaua / The Sweet Science". In "Pa'a Ka' ipuka I Ka' Upena Nananana", he was badly wounded and died in surgery from cardiac arrest . His daughter Sarah is currently being cared for by Chin as her legal guardian . </Li> <Li> Michelle Shioma (Michelle Krusiec) is the daughter of the late Goro Shioma and his successor as head of the Hawaiian Yakuza . Introduced in season 6, she is seeking revenge after Gabriel Waincroft has her father assassinated in an attempt to gain control of the criminal underworld in Hawaii . She is married with two daughters . It is mentioned in season 8 that she had been murdered in prison . </Li>

Who plays chin ho kelly's brother in law