Spacing with Fair, Dtilt, and Ftilt are good. If they shield a lot, grab them. fair is NOT SAFE on shield btw
If you grab them at low% (around 0-20%) and they DI down and away your dthrow, you can actually ftilt them and this is almost always guaranteed.
If they DI up, uair them. If they air dodge after DIng up, you can uair> nair and this will connect basically all the time. M2K showed me this at Apex
Ftilt 3 out ranges everything MK has. Dash attack can be good for a surprise approach, but it can be shield grabbed easily so using this predictably is really bad.
You should always fast fall your F-Airs, but to do this properly you must wait until the F-Air animation ends, THEN fast fall. Otherwise, you will have more landing lag than normal and the F-Air will not auto cancel. If you do it correctly, the lag is pretty hard to punish, but MK can D-Tilt the other since it has great reach and it comes out very fast. If you space it correctly, it's safe if they shield it.
MK's sword has transcendant priority, so all of his non B moves except dash attack and glide attack will beat out tornado.
TORNADO VS TORNADO: I asked M2K about this and there are 2 factors to it. The tornado that is higher up and pressed more B usually wins. This makes sense because Tornado's hitboxes are put together so it's like a cup, and at the top is where MK is vulnerable.
If they approach a lot with dash attacks you can also SH/FH dair.
Grounded SL is a good way to punish things out of shield. This kills at around 130% fresh with no DI.
If you GSL, and miss, the other MK will probably try to punish you with their own GSL.
IF YOU KNOW THEY WILL DO THIS, DO A GLIDE ATTACK ASAP because it will trade hits with their GSL and they take more damage. I'm not sure if this is 100% guaranteed, I just saw M2K do this a lot.
If you see the other MK miss their GSL, usmash covers all options. It doesn't really do much damage, but this way you don't take damage. You can also start juggling them with uairs, this is good too
BTW if you get D thrown at low %, you can also buffer an air dodge and then ftilt right after. This can catch the other MK off guard.
MK can actually "chain grab" MK. If MK air releases, you can dash grab them and this is a guaranteed regrab. If they ground release, I don't think there's anything guaranteed.
When you are above MK, you're at a disadvantageous position. It's safe to jump a couple times and then glide away to the edge so you don't get juggled, but you also need to make sure you have jumped high enough so the MK can't shuttle loop you or hit you with uairs.
If you are the one doing the juggling, if they don't do the glide thing, space uairs and fast fall them and it is easier to space like that. Uair is also faster than dair, so you don't always have to fast fall.
When MK is off stage, you should stand at the ledge. If they recover low, but high enough, do a ledge drop nair > reverse SL so it auto snaps the ledge. This can be good for edge guarding. If they are smart then they will stay lower and throw uairs and that can beat your ledge drop nair.
One thing I see M2K do is he will grab the ledge and do a ledge drop Tornado if the MK is below. Use this if you know they are going to try to recover with SL, because Tornado will suck in MK if the MK does a SL.
Like this:
http://www.youtube.com/watch?v=z0QpYIvLiPY#t=0m21s
If the MK is recovering with nado, you can do a ledge hop bair, and this can be good sometimes. I saw M2K do this a lot at SuperCon recently, and it can work really well. You just have to know when to use it as the tornado comes. It's not that hard to space either.
http://www.youtube.com/watch?v=jMaV7f-Dmd8#t=2m04s
If their nado is above you while you are grabbing the ledge, uair them. That's all you can do pretty much if they are above you.
If you know that they will try drill rush, time it so you grab the ledge, and do a ledge drop nair. I saw M2K do this at apex and it can stage spike in a really weird angle. I'm not really sure how to explain it.
If the MK is gliding at you, tornado them. They get sucked in really easily and glide attack doesn't beat Tornado.
Let's say you grab the ledge. It's pretty safe to start planking and wait to see what they will do. They will most likely charge an Fsmash. Charging an fsmash is fairly safe because it out ranges a ledge hop fair. DO NOT DO A LEDGE HOP FAIR this is a bad option in general.
What you can do to stop them from their fsmash charging is plank and then recover with a surprise tornado. This usually works if they dont expect it. Another thing you can do is ledge drop, then jump> airdodge onto the stage and quickly buffer all 3 hits of ftilt because this out ranges fsmash. The spacing and timing for this has to be really good so don't do it stupidly.
Don't fall for the tearbear stare. Fsmash has little lag and trying to punish it often ends up you taking damage instead. Uthrow kills at around 170% ish iirc.
If you are gliding to the edge, and the MK is standing at the edge charging an fsmash, glide attack can actually beat this if you tilt up your glide SLIGHTLY. If not, it's like 50/50 may trade hits
When you are recovering, tornado and DC are probably the safest. Tornado is really versatile in terms of mobility so you can keep your opponent guessing where you will land/how fast you will go etc. DC makes you invincible for a couple frames and has minimal lag so it's not bad either i guess.
gliding low and stopping at like a 45 degree angle from the ledge and throwing uairs is pretty safe. then you can DC onto the ledge/on stage. if you grab the ledge, and the other mk is standing at the ledge they can fast fall off the ledge before you grab the ledge and if you let go of the ledge to try to start planking they can uair and you can possibly get stage spiked
grabs are really really good, edge guarding/juggling is where i get most of my damage
STAGES: Ban your least favorite stages, and CP your favorite ones. LOL
That's all I know