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.