He was created to be "an older gentleman" and is an enigma to even the creators. Developers consider his moves to be comical compared to the seriousness of his image, especially the move Joker when it is blocked or misses. They chose to leave the result of his fight with Shen ambiguous, implying that fans would have been disappointed with the outcome. He was originally intended to be the "good-looking glasses" character for the series.
He is voiced by Toshihiro Shigetsuka.
Oswald is a man who is said to be a professional hitman. Ash requested for Oswald to join the tournament based on rumors he heard about him. Since neither knew much about the other, the conditions for joining the team was decided in a poker game; the winner would choose to do what they pleased. Despite having a winning hand, Oswald recognizes Ash's skill and accepts defeat - he introduces himself to his teammates then.
It is revealed at the end of the tournament that Oswald joins Ash and Shen Woo to obtain money and drugs named 'Dragon Pills' (or 'Ryu-gun' in Japanese). Ash agrees to give information regarding the drug to him, explaining that it can only be given to him if he defeats the provider's enemy, Shen Woo. As Ash left Oswald and Shen alone by themselves, a battle between the two took place, the winner of which has yet to be revealed; though the confirmed survival of both Shen and Oswald makes either outcome equally plausible.
Oswald is a quiet and very serious man who is willing to do anything in order to achieve his goals, even going as far as to kill. He acts like a professional and is not touched by concepts such as morality.
- Blending with shadows - Oswald is able to blend with shadows. His clothes are not affected by this power.
Oswald fights with his slashing playing cards akin to knives, using a unique fighting style named after Karnöffel; his suit moves (Spade, Diamond, Club and Heart) can all be uniquely chained-together as a focal point of his gameplay. Many fans have noted that Oswald's card-based fighting style is remarkably similar to X-Men's Gambit (this comparison is most obvious between Oswald's Joker LDM and Gambit's Royal Flush super). Oswald even has a super named Royal Flush, but is done differently from Gambit's version.
All of Oswald's moves are officially rendered with playing card symbols (e.g. ♠ = Spade, Q = Queen, ♠♥♦♣ = Four Suits, 10・J・Q・K・A = Royal Flush and so forth).
Gameplay-wise, Oswald is considered one of the top 3 characters in The King of Fighters XI, with many people considering him the third best in the game right behind Gato and Kula Diamond. It should be noted that unlike most characters' standing/crouching weak punches where they usually can get two in at best, Oswald can cheaply land four to five jabs on his foe creating powerful combos due to both the speed and range of the attacks.
- Joker - The King of Fighters XI
- The King of Fighters XIII - in the Elisabeth Team's ending
- Days of Memories (fourth title) - cameo with Ash