Also in Tekken 3, Heihachi could chain Demon Uppercut to the Spinning Demon (Hell Sweeps) in the same way he could the Dragon Uppercut and Tsunami Kicks, however, the chain was removed in later games thus only made its appearance in Tekken 3.
The Demon Uppercut's command input is f,F+2. During the animation, Heihachi performs an all-out uppercut that sends the opponent straight up in the air on hit, and while it can be a bit slow to come out, the reward is the highest launch Heihachi will be able to muster. In the case of Tekken 3, the chance to perform some of his most damaging combos increases once the move successfully connects the opponent.
When to use
The Demon Uppercut is fairly slow, like the Dragon Uppercut, although the player doesn't need to initiate a crouch dash to set the move up. It is able to duck under all high attacks, and right before the punch itself, most mid attacks as well. This makes it a relatively good counter-attack when one anticipates the opponent to dish out a high-mid string, however, because of the often better alternatives which can also lead to juggles, the stand-alone Demon Uppercut is rarely, if ever, used in high-level play.