Another thing is that Up-Air "sucks" the opponent in order to hit with all hits. If you hit with your Up-Air at a very specific range and fast fall the attack you will actually BRING your opponent with you. I've only been able to do it 3 times and they have happened randomly (since I always fast fall my aerials anyways).
This is one of what I call the "four noble ninja truths", that the U-Air can be used to drag the opponent down.
I don't believe range plays a role in the technique, and more importantly I believe all 4 of the first hits will drag the opponent down so it should be fairly simple to utilize as long as they are not getting hit by the 5th hit - this fifth and last hit has the KO potential though, so it is important to use in many situations.
Fast-falling is not necessary, but the best way I have found to successfully pull this technique off is to utilize a fast-fall immediately after using the U-Air at the pinnacle of the jump (either short or full jump). With this timing Greninja will hit the ground and cancel the attack after the 4th hitbox allowing for maximum damage.
The landing lag is actually quite considerable, IMO, so it is important to space at his toes so you have more distance between Greninja and the opponent giving Greninja a few extra frames to get through his "kip up" as he gets to his feet for a follow-up attack.
I like to call this technique "Gravity" a move from Pokémon which brings flying opponents down to the ground (although I don't think Greninja learns this, so Smackdown could work).
But what should you follow up with? Well, if you space the attack well enough you may be able to consecutive hit with an U-Tilt (Greninja used Lick. The opponent became paralyzed!) and follow-ups can happen from there depending on circumstances. Note that you will want to have the correct facing with the U-Tilt as the swinging arc of his tongue matters in if you will score a consecutive hit or not (don't want your opponent Shielding between U-Air and U-Tilt, otherwise you could be in big trouble as the U-Tilt cool-down is quite considerable on a shield).
I think the D-Tilt may be able to work as a consecutive follow-up as well, but I haven't given this a thorough test.
Like this Noble Ninja Truth? The others are just as good o__o ribbit
Use this information for matchups. I think the Up-B trick, once mastered will allow Greninja to dominate Little Mac.
It really won't be the end-all decision for that matchup, but there's plenty of potential for its use against Little Mac, mostly against his abysmal recovery. You can U-Spec (Waterfall?) off the stage away from the stage at Mac and then change direction back onto the stage to knock him away with a surprising Stage Guard. Keep in mind that if you are on the ground then you will not get that second "jaunt", only one shot forward, so I am not sure if you can do this without SDing unless you either run off the edge or jump immediately before using it (try going for a "flick jump" hand technique on the controller for this to make it easier). But if you can do this by simply going off stage no further complications would be needed to remedy (I'll test it out and see).
A note about the U-Spec: The move will fire 4 "blobs" of water out away from Greninja as he (waterfall/hydropump/hydrocannon/watersport/whatever) each of these will score damage (I think 2%?) and has "gust-like" affect on an opponent (and I think some/all items). Just remember they shoot away from Greninja as he flies the opposite direction, which is opposite the direction the opponent will be pushed - don't get confused, it could cost you a stock.
