Blue Mary (ブルー・マリー), whose real name is Mary Ryan (マリー・ライアン), is a character from both the Fatal Fury and King of Fighters series of fighting games. Blue Mary's first appearance was in Fatal Fury 3: Road to the Final Victory as a private detective. According to Neo Geo Freak, she is modeled after Android 18 from the Dragon Ball series. Her official nickname is Woman in S Class (Sクラスの女, Esukurasu no on'na). 
In the Neo Geo Freak's 1997 Volume 8 character poll, she was voted as the fourteenth favourite character with a total of 705 votes.  And In the character popularity poll on Neo Geo Freak's website, she was voted as the fifteenth favourite character with a total of 857 votes. And in Neo Geo Freak's August 1998 issue, she was ranked as the 9th best character. 
Her former lover, Butch, and her father had worked together as fellow colleagues in the secret service. While on a mission protecting the president, they were both shot and killed by terrorists. Devastated by the loss, it is said she has never smiled again since the incident. The leather jacket she wears is a keepsake given to her as a gift from Butch.
Having been taught by her former lover how to fight, she becomes a freelancer. Throughout the series, she takes on various odd jobs to investigate mysterious cases. During this time, she meets Terry and the two become good friends.
The King of FightersEdit
During the outcome of the tournament, it was discovered that Yamazaki had become more and more insane due to the Orochi blood coursing through his veins and that Billy was sent by Geese to keep an eye on him in order to learn the secret of the Orochi power. However, during a moment of confusion, Yamazaki escaped and Mary was left to ponder on Geese's motives and the root of the situation.
Following its conclusion, Terry Bogard informs her of the NESTS cartel and their actions occurring in Southtown. With a new goal in mind to stop the organization, Mary joins the Women's Team along with King, Kasumi Todoh, and Li Xiangfei, and the "Lonely Wolves" in 2000 and 2001 to assist in stopping NESTS in the following tournaments, eventually leading to its demise.
In 2003, she joins the tournament to investigate the movements of Those from the Past and teams up with former teammate King, as well as another Fatal Fury Team alumna Mai Shiranui. In KOF XI, Mary teamed up with Vanessa and Ramon to continue her case.
Blue Mary is very friendly towards everyone, but she knows (or thinks) that her job must come first before everything else. Mary developed a strong bond with Terry, they seem to have a genuine care and fondness with each other.
- Ignore weight: Mary can throw her opponents, regardless of their weight.
- Energy Attacks: Mary can fuel her attacks and throws with ki energy. It can be shown as a red rose, a pink splash or red/blue streaks.
- Motorcycle Riding: Mary knows how to ride a motorcycle very well.
- Detective skills: Blue Mary has had extensive training in deep background investigation.
- Kiss Me - Fatal Fury 3, Real Bout Fatal Fury, and The King of Fighters '98: Ultimate Match (as EX Mary)
- Blue Mary's Blues - Real Bout Fatal Fury Special, Real Bout Fatal Fury 2, The King of Fighters '97, The King of Fighters '98, and The King of Fighters '98: Ultimate Match. A music video of this song was a reward for those who beat Real Bout Special with Mary.
- Sha La La - The King of Fighters '99
- Terry 115 - The King of Fighters 2000
- All OK! - The King of Fighters 2001
- Yuuwaki no Toki (The Alluring Time) - The King of Fighters 2002
- I'm Hot for You - The King of Fighters 2003
- Secret Circumstances - The King of Fighters XI
- Masquerade - The King of Fighters 2002 Unlimited Match
- Kiss Me ~KOF XIV ver.~ - The King of Fighters XIV
- Harumi Ikoma - The King of Fighters '97 - XI
- Sarah Emi Bridcutt - The King of Fighters XIV - present
- The Remains of My Love -The Sunset Sky Part Ⅴ- - Fatal Fury 3
- Blue Mary's Blues - Real Bout Fatal Fury Special
- Dance de Peace! - Shared image song from the Scitron 10th Anniversary Special: Fatal Fury -Selected Characters-
- Fatal Fury 3: Road to the Final Victory
- Real Bout Fatal Fury
- Real Bout Fatal Fury Special: Dominated Mind
- Real Bout Fatal Fury Special
- Real Bout Fatal Fury 2: The Newcomers
- The King of Fighters '97
- The King of Fighters: Kyo
- The King of Fighters '98
- The King of Fighters '99
- The King of Fighters 2000
- The King of Fighters 2001
- The King of Fighters 2002
- The King of Fighters Neowave
- The King of Fighters 2003
- The King of Fighters XI
- KOF Maximum Impact Regulation "A"
- The King of Fighters '98: Ultimate Match
- The King of Fighters 2002: Unlimited Match
- Garou Densetsu Special - event character
- The King of Fighters XIV - DLC character
- Days of Memories (second title) - non-playable
- The King of Fighters Mahjong
- KOF Gals Mahjong
- Moeyo! SNK Gals Osuin Katoukai
- SNK Gals Island Dokidoki Puzzle Shock! 2
- SNK High School Collection
- The King of Fighters '98 Ultimate Match Online
- Kimi wa Hero
- The King of Fighters All Star
- The King of Fighters: Orochi Go
- The King of Fighters: Destiny (Game)
- The King of Fighters M《格鬥天王M》
- The King of Fighters '95 - in the Japan Team's stage
- The King of Fighters '96 - in the Fatal Fury Team's stage
- The King of Fighters XII - mentioned in Terry's sidestory
- The King of Fighters XIII - gives Terry a ride to Pao Pao Cafe and talks with his team in his team's backstory, appears in Story Mode and Fatal Fury team ending
- The King of Fighters XIV - in the Fatal Fury and Women Fighters Teams endings
- KOF: Maximum Impact - background cameo
- KOF: Maximum Impact 2 - background cameo
- The King of Fighters '94: Rebout - background cameo in the Women Fighters Team stage
- KOF Sky Stage - Terry’s ending
- Garou Densetsu The Legend of Wild Wolf
- The King of Fighters (pachinko)
- The King of Fighters 2
- Nariyuki Quest
- The King of Fighters EX: Neo Blood - mentioned in Fatal Fury Team's ending
- The King of Fighters EX2: Howling Blood - in the Fatal Fury Team's ending
- The cocktail she takes her alias from is a mysterious drink. From the drinker's perspective, the drink is a deep clear blue. From other angles, it appears to be transparent like water.