Tekken 6 Storyline
In The King of Iron Fist Tournament 5, King faced Marduk in a grueling battle that ironically resulted in a friendship between the two after the fight. Upon returning from the ring, Marduk was ambushed by someone dressed as Armor King. King was furious and vowed to find the culprit, but was unsuccessful in his attempt.
With the world engulfed in war, King all but gave-up looking for Marduk's attacker when he received an invitation from Marduk to join him in The King of Iron Fist Tournament 6. If they both participated in the tournament, perhaps the Armor King imposter would appear once again. With that hope in his mind, King decided to take part in the contest.
Source: tekken.namco.com
Tekken 5 Storyline
After defeating Craig Marduk, King headed to the boastful
Austrlian's hospital room to finish him off and avenge his master's
muder. But at Marduk's bedside, King realised the foolishness of his
desire for vengence and walked away. After Marduk declared his craving
for a revenge match at the King of Iron Fist Tournament 5, King roared,
"I will not stand by and allow my mentor's name to be disgraced!"
Source: Tekken 5 manual
Tekken 4 Storyline
News reached King that his mentor Armour King had been
knocked unconscious by a mysterious Vale Tudo fighter during a bar
brawl. Armour King died hours later.
Kiing vowed to kill his foster-father's murderer with is own hands. Using money he had won on the professional wrestling circuit, King paid for the man's release from prison and mailed him an airline ticket and a newspaper article featuring an excerpt advertising the King of Iron Fist Tournament 4. King then set off for the tournament himself, ready for a final showdown with this mysterious Vale Tudo fighter, his sworn enemy.
Kiing vowed to kill his foster-father's murderer with is own hands. Using money he had won on the professional wrestling circuit, King paid for the man's release from prison and mailed him an airline ticket and a newspaper article featuring an excerpt advertising the King of Iron Fist Tournament 4. King then set off for the tournament himself, ready for a final showdown with this mysterious Vale Tudo fighter, his sworn enemy.
Source: Tekken 4 manual

