As an infinite, it isn't very reliable because the Metal Blade randomly disappears. Look up some videos featuring Kamemushi's Mega Man instead. That guy has the footstool combos down!
Late reply yeah, but I was thinking about this earlier today and was curious if there may be a way to make the combo a true 0-death by throwing the blade mid combo after it despawns. Afaik this was never done before, but turns out there is indeed a way to extend the combo using z catches and blade tossing mid combo.
Video showcasing the concept:
Messed up at the end but I think you can understand what I'm getting at here. Obviously you don't need to start with the b reverse like I did in the video, it can start from a regular footstool combo. This extension only applies to when the blade despawns.
While this should be a true combo, it only is true if you manage to get 2 hits from the metal blade toss. Haven't managed to make the combo true with just one hit from the blade yet. Main trick with making sure you get both hits is spacing. In order for this to work you need to jump backwards a little bit to make sure the angle is good, then you can start moving towards your opponent so you can reach them quick enough. Depending on how far back you need to jump to make the angle good depends on how far away you land after the lemon lock, so use the spacing in the video for a reference and mess around with it in training mode.
After you get the 2 hits, the inputs are as follows: dash forwards SLIGHTLY, jump, return control stick to neutral, grab the blade, jump(footstool), buffer grab for the z drop, continue the rest of the combo like normal. The inputs need to be incredibly quick, and if you aren't used to doing stuff like this it can be pretty difficult to learn. Just practice every now and then and eventually it should become muscle memory.
Haven't tested on everyone obviously but in theory this should be true on everyone the normal footstool combo works on, as long as you can get the 2 hits from the metal blade toss.
Congrats robots, you can kill at 0.