What happened exactly when i press all four buttons?

[Ares4X]

There is a different stance animation yes and my fist have a golden aura around. But do i more damage in this "pose"? Guess not, doesn't change anything in Training Mode.
Thanks in advance

[The Phantomnaut]

Ki charge. Basically any move that hits becomes a counter hit. That said, you cannot block at all so your opponent just needs to find the right launcher at the right time and you have to eat the damage.

[Mr Daylight]

Ki charge is as old as Tekken 1. It makes you unable to block and all hits that land on your or your opponent are now CH (counter hit). It can also have some special properties with some characters and moves. Some characters Ki charge off of moves like Leo. It can be used in strategy. I believe an early T7:FR tournament was won by a player using Ki Charge to bait an attack and then used RA (rage art). It has all kinds of uses and despite being as old as Tekken, it's still a niche tactic. Not to be used lightly.

[Ares4X]

Thanks guys for the detailed replies!

[Discane]

Leo gets happy.