Please note: This name is Korean; "Baek" is a surname, not a given name; the given name of this character is "Doo San".
Baek Doo San (Hangul: 백두산; Hanja: 白頭山 Baek Du San; Japanese: ペク・トー・サン Peku Tō San; It may be written with given name first as Doo-San Baek) is a character in the Tekken series. Baek first appeared in Tekken 2, and he has returned for most titles with the exception of Tekken 3, Tekken 4, and Tekken 7.
In Tekken 2, Baek first appears as Marshall Law's Stage Eight sub-boss. This is because Baek was blackmailed into destroying Law's dojo by a competitor of Law's who knew the truth behind Baek's father's death. In Tekken 3, Baek is not present but he was, in a sense, replaced by his pupil, Hwoarang.
In Tekken 2, Baek is shown as a man with a troubled past who is unwillingly made to do questionable deeds.
However, from Tekken 5 and onwards as the master of Taekwondo, Baek shows as being serious and a good man but being a strict person especially to his student Hwoarang. He also disapproves Hwoarang for street hustling as seen from his ending in Tekken 5. He is also shown to be a risk taker as seen in his Tekken 6 ending where he saves Hwoarang at the cost of his life. Therefore his sorrow and his traumatized past still remains within him as he still remembers how he killed his father in his ending in Tekken Tag Tournament 2.
Baek Doo San, a master of Taekwondo, is the son of a former Taekwondo champion.
During his childhood, his father received a career-ending injury. Devastated, his father turned to alcohol and became a heavy-drinker, which ultimately led to his incarceration.
Plunged into a life of poverty, the young master's family was forced to deal with hard times, and just when things looked as though they couldn't get any worse, his mother disappeared, leaving him and his siblings alone. Not too long after that, his father escaped from prison to assist the family, but due to the deprivation of proper nourishment, Baek mistakenly killed his father, a man he respected above all else.
The frightening experience left him traumatized, driving him crazy every time he saw blood. When the police found him, they took him into their care and raised him.
Years later, he found himself walking the path of his late father, a Taekwondo master, and champion, but unfortunately, a person knowing the truth about his father's death threatened to go public with the truth of his past if he didn't destroy his blackmailer's competition.
The attack on the martial arts school Marshall Law instructs at took place while the school's instructor was away; a confrontation between Baek Doo San and Marshall Law is inevitable. Baek was eventually defeated by Law in the tournament. 
Ending Description: Baek is seen sitting on a bench outside a park. He takes out a locket containing a photo of him and his father. Baek reminisces about his training sessions with his father, remembering the great person he was and how much he loved him. Remembering his father for the man he was, Baek finds peace within himself and he forgives himself for killing his father.
According to the Tekken 3 storyline, Baek was presumed dead after encountering Ogre, the fictional Aztec God of Fighting. One of his closest students, Hwoarang, entered The King of Iron Fist Tournament 3 to exact revenge for his master's death and to also have a rematch with Jin Kazama, the only fighter who had ever fought him to a draw.
Ending Description: When his student Hwoarang is about to fight three thugs in the street, Baek immediately calls his student after seeing him doing street hustling and he angrily disapproves his actions as one of the thugs knock Hwoarang with a single kick. The three thugs are soon to confront Baek, Hwoarang attempts to stop them which Baek becomes angry towards them as he quickly defeats them in proccess as Hwoarang watches. Hwoarang shrugs as Baek strictly drags him while walking away.
Baek entered The King of Iron Fist Tournament 5, along with his disciple, Hwoarang. However, Baek withdrew from the tournament when he found out that Hwoarang lost to Devil Jin, and he was seriously injured. Baek then rushed to the hospital to visit Hwoarang. Although Hwoarang's condition wasn't considered as something serious after his treatment, Hwoarang wouldn't wake up, and Baek started blaming himself for being an inadequate instructor.
It took Hwoarang three days to regain consciousness. They discussed the details, and Hwoarang told Baek that he not only has to recover, but he has to strengthen himself even further. Baek sensed his strong will and his unprecedented modesty, and hence he decided to teach him everything he knows. Baek and Hwoarang returned to Korea, and endeavoured to practice intensely. Eventually, the announcement of The King of Iron Fist Tournament 6 came from the Mishima Zaibatsu, and Baek decides to enter the tournament one last time to widen his personal experience-collection.
Ending Description: Baek has defeated Azazel. Hwoarang then comes in, asking if he is all right. As soon as he gets up, so does Azazel. However, as Azazel is about to attack, Baek finishes him off by front-kicking him. Azazel's orb broke and he broke to pieces. However, Baek falls to the floor after risking his life to save Hwoarang, while the latter cries for his master to not die (not knowing that he was too late).
Baek made a minor appearance in Tekken: The Motion Picture, he is shown fighting and being defeated by Kazuya Mishima.
Baek appeared as a playable character in Tekken Tag Tournament.
Baek returned as a playable character in Tekken Tag Tournament 2.
Ending Description: Baek is seen in his dojang reminiscing his time together with his father. He then punches the floor as he remembers the time he accidentally killed him. Hwoarang, who was secretly watching, becomes concerned for his master, and decides to let Baek get mad at him to distract him from his sorrow to lighten him up and does so by shouting that he had overslept and his hopes that Baek doesn't catch him. He does this staying just out of sight (but not earshot) and pretending to boast about getting away with oversleeping and arriving late, leading Baek regain his sense reminded he has a family like Hwoarang, who considered him being one of him. Hwoarang's plan succeeds and backfires at the same time as an incensed Baek tells him to do a thousand pushups for his "tardiness".
Despite being generally clunkier and far less aggressive than Hwoarang, Baek is still to be considered a very agile and fast-paced character.
Baek’s moveset is much more balanced than Hwoarang’s, offering somewhat less efficient but still devastating kicks, decent punching capabilities and a few good counters as well. Baek is best-suited for a balanced style that relies on the long reach and raw power of his kicks mixed with a few quick punches here and there to keep up the pressure.
Despite having good offensive capabilities, pure aggression can be a risky approach against faster characters due to his somewhat sluggish recovery between attacks. Also his about average defense pales in comparison with the likes of Kazuya, King and Steve for example.
In a nutshell, Baek is a quite strategic character while still remaining on the more beginner-friendly side of the spectrum.
Baek fights using Taekwondo.
- Hwoarang - His student, and ally in the Resistance in Tekken 6. While Hwoarang's unruly nature sometimes causes Baek grief, he is still shown to deeply care about his pupil.
- Marshall Law - Baek attacked Marshall's dojo in the events of Tekken 2, and was eventually defeated by Law in the tournament. Marshall is also his sub-boss in Tekken 5.
- Mr. Baek - His father and mentor, whom he accidentally killed during a sparring session.
- Ogre - He was put into a coma for over a year by Ogre, before the events of Tekken 3.
- Kazuya Mishima - Baek was defeated by him in Tekken: The Motion Picture (non-canon) and is his sub-boss in Tekken Tag Tournament.
- Wang Jinrei - His possible sub-boss in the arcade version of Tekken 2 (if he in place of Jun Kazama).
- Jin Kazama - Baek has a grudge against Jin for severly injuring Hwoarang in the fifth tournament (which he actually did in his Devil form). Also the main enemy of the Resistance in Tekken 6.
- Miguel Caballero Rojo - His ally in the Resistance in Tekken 6.
- The name "Baek-Du San" is that of a mountain that is split in two by the North Korean-Chinese border. It is treated almost like a national monument by the South Koreans.
- His given name, "Doo-San", is patterned after one of the ITF's 24 patterns, "Do-San", consisting of 24 movements.
- Baek is a 6th dan black belt, as evidenced by the six tags on his belt.
- Baek's name is written in the Hangul alphabet as "백두산", and in kanji as "白頭山". In both cases, it means "White head(ed) mountain".
- Baek was attacked by Ogre between Tekken 2 and Tekken 3.
- The uniform that Baek wears is called a dobok. Meaning "way of life training clothes" in Korean, the dobok is the uniform for Taekwondo, modeled after the Japanese gi for the basic look and the v-neck for the hanbok.
- Baek Doo San is also the name of a fictional character in Korea, who was a great taekwondo master who lived in Japan.
- There is a possibility Baek could be based on Hwang Jang-Lee.
- In Tekken 7, one of Hwoarang's customizable items is Baek's TK5 & TK6 2P suit. He can also be given the generic beige fedora and a gray beard to make him resemble Baek even more.
- Owners of the Tekken 2 arcade machines were given the option to set either Jun or Baek as one of the ten default characters displayed on the selection screen (in the Playstation version, it was Jun who was placed on this spot). This was accessible via a dip switch.
- Baek is Marshall Law's sub-boss if not placed as a default character. Once unlocked, Marshall Law is his sub-boss.
- If placed as a default character in the arcade machine of Tekken 2, Baek's sub-boss is Wang Jinrei, and he will be Wang's sub-boss if Wang is unlocked.
- His Stage 7 sub-boss is Kazuya Mishima.
- Baek's sub-bosses are Marshall Law and Hwoarang. He's also Hwoarang's stage 4 sub-boss.
- While playing as Baek, he meets Marshall Law in the story mode. However, neither of them reminisce about the events in Tekken 2, as if they have not yet met each other. After Baek defeats Marshall, Baek says, "I hold instructional sessions on Sundays at my dojo. Why don't you join in on one of my sessions?".
- He is unlocked by beating story mode 3 times with a different character.
- In the Scenario Campaign of Tekken 6, Baek is a boss at the West Coast Canal Industrial Complex and is in an alliance with Hwoarang and Miguel.
- If you use Baek in Marshall's Stage in Scenario Campaign, Marshall will mention their meeting during the events of Tekken 2 before the boss battle begins.
- Baek appears in the last part of Wang's ending alongside Ganryu.
- In the Ghost Battle mode, one of Baek's possible partners is Miguel, likely due to them being allies in the Scenario Campaign.
- While he doesn't appear and is never seen in the game, Baek is mentioned a few times in Hwoarang and Steve's story in Street Fighter X Tekken.