A native of Curitiba, Brazil, Cristiane Justino Venancio was born in 1985. Famous as Cristiane "Cyborg" Santos, she shares the nickname "Cyborg" with her husband and fellow mixed martial artist Evangelista Santos. Cristiane's first professional fight was with the Brazil-based Showfight promotion in 2005. She fought Eric Paes who submitted her by knee-bar early in round one. Her first MMA win happened that year in her second bout which happened with local promotion, Storm Samurai. She won unanimously over Vanessa Porto at "Storm Samurai 9". In 2006, she would experience the most MMA success with three consecutive wins over opponents in the first round: Chris Schroeder by TKO at "Storm Samurai 10"; hurting Elaine Santiago at "Storm Samurai 11" to earn a corner stoppage victory, and Marise Vitoria at "Storm Samurai 12".
After a two-year absence from MMA competition, Cristiane returned to action in July 2008, for her first fight in the United States. It happened at the "EliteXC Saturday Night Fights: Episode #1.2" (2008) event titled "Unfinished Business", which aired on CBS. Cyborg used her strength to dominate Shayna Baszler for 2 rounds before the fight was ended by TKO. One of the fight's notable moment includes Cristiane sending Baszler to the ground after overwhelming her with strikes then prematurely celebrating. Months later in October at "EliteXC Saturday Night Fights: Episode #1.3" (2008), named "Heat", Cyborg won unanimously over Yoko Takahashi, in one of her few fights to go to a decision. The non-title bouts with Baszler and Takahashi were scheduled for three 3-minute rounds, unlike the usual three 5-minute rounds for men in non-title fights. Several days later after "Heat", "Elite XC" (2007) went out of business and ended any prospects of a much discussed fight between Cyborg and Gina Carano, who also fought in the promotion.In 2009, "Strikeforce" (2009) acquired former properties of Elite XC, including the video library and fighter contracts, which included Cyborg's. Cyborg moved to "Strikeforce" (2009) under an exclusivity agreement, and had her first fight with Hitomi Akano in a bout scheduled for 3 three-minute rounds. Cyborg again used her strength and size advantage to dominate Akano to a TKO victory in the 3rd round.With Gina Carano also under contract, Cyborg's much speculated bout with Carano was booked on August 15, 2009. Strikeforce held its first MMA event headlined by women: Strikeforce: Carano vs. Cyborg (2009) (TV) scheduled for the conventional five 5-minute rounds for championship MMA bouts. The fight would be for the Strikeforce's women's "middleweight" title at a 145 pounds weight limit usually known as "featherweight". Cyborg defeated Gina Carano by TKO one second before the end the first round, becoming Strikeforce's first ever women's champion. Cyborg's first defense of her Strikeforce championship (145 pounds) would happen against Marloes Coenen--whom she was to have fight at XMMA 7 in Montreal--at Strikeforce: Miami (2010) (TV). Coenen brought a competitive fight to Cyborg, who successfully defended the title in the 3rd round with a TKO win. After her first title defense, Jan Finney was later announced as the next contender for the title. Cyborg and Finney fought at Strikeforce M-1 Global: Fedor vs. Werdum (2010) (TV), which ended in the 2nd round after Finney was knocked out by Cyborg.