Leo Kliesen (レオ・クリーゼン Reo Kurīzen?) commonly known as Leo (レオ Reo?) is a character from the Tekken fighting game series by Namco. Leo is one of several newcomers first introduced in Tekken 6. Leo is from Germany and uses the fighting style of Baji Quan. Leo entered the King of Iron Fist Tournament in the hope of uncovering more about his deceased mother, who had been a researcher for the Mishima Zaibatsu.

When Leo learned that his battle arena was to be a Zaibatsu-owned dojo, he couldn't believe his luck. However, when he got there, the dojo was in ruins. The moonlight poured in through holes in the walls and roof, illuminating the floor with an eerie beauty. A short while later, a strange, floating silhouette appeared, and slowly glided toward Leo. The silhouette held a sword in its left hand that rotated at a mind-bending speed. What the hell was this thing? It looked like some kind of a flying squid or octopus! Was it a demon...?

Then it finally dawned on Leo: This bizarre creature was his opponent. Cautiously, he prepared to fight. Ending Description: After defeating Yoshimitsu, Leo ponders as to what he is exactly. Bending down, Leo pokes at one of Yoshimitsu's tentacles and immediately jumps back in shock when it starts to squirm. Remembering the mission, Leo bids Yoshimitsu farewell and leaves.