I think you mean MK dair camping, and usually what you can do is charge mortars, or just mortars in general can help. Even better are usually making grenade walls to hit him.
As for the actual matchup, it's really important not to get grabbed at the edges because that is more likely than not going to turn into a really ugly gimp. He pummels until release and you have no good options for recover honestly. We all know he gimps us like a real *******, so practice recovering and landing like 10000 different ways. Aside from gimping offstage, when you go high off the screen to recover, MK can do a few things, they can tornado you, but this is beaten by either pulling a grenade and maybe killing both of you or you can just airdodge right through it. They can also up air juggle, but this is dangerous to airdodge as he can do two while you airdodge and catch you still, b reversing away from him or dropping a nikita can help this. Sometimes they'll try to shuttle loop you at the top of the screen and if they miss they'll chase you with the glide, this is fine as you can easily b reverse away from that.
As for edge guarding MK, the standard mortar wall/grenade at the ledge/c4 drop are your best options. Edge hogging has never worked out for me well unless they f'd up and were already in a helpless state, but if you shield a shuttle loop at the edge and they don't sweet spot you can ledge hug and this has worked out as most MKs don't try to glide to the other side.
Generally at lower percents, I like to not plant c4s because I might need them to recover, speaking of which when you c4 hop he might fly up to you and try to get it planted on him just pivot and c4 jump.
The tornado is super annoying, but you must learn to uptilt on reaction but definitely learn to pick your fights. I've heard that you can pivot grab the tornado, but I've not been able to do it, if someone else has and it worked I'd like to know. If they're tornadoing at you from one side of the stage you can literally just run away from it, and if they continue to chase you till it ends you pivot grab. We all know grenades can stop and punish the tornado so that's pretty standard, however if shield dropped they can tornado the top of your shield. I think, not absolutely sure, but it seems like a certain timing with the dash attack can beat the tornado, as said in the hitboxes video there are a small amount of invincibility frames, this has worked a few times for me.
His grabs put you in terrible positions, especially dthrow. At low percents he can dthrow you and run and dthrow you again if you don't try to land and grab him first. However this situation is advantageous to him because instead he can just follow up with aerial, and if you shield all the time he'll come with a grab. However, near any time he can dthrow -> tornado and that can be shielded, but only if you DI away. As far as I know the best way to DI the dthrow is always away, because if you DI up you're asking for a shuttle loop/tornado/aerial that will lead to a gimp.
Definitely use the grenade wall that Ally uses against MKs. Soft toss one cook the second and toss. Having a grenade in your hand is usually pretty beneficial in the air, because if shuttle looped it'll explode unless he hit you from directly under which will hit you at a less lethal angle/knockback I'm pretty sure. And DIing a grenade gives you a much higher chance of survival.
- Minor things -
Avoid omnigays by either getting fourth port, or just being aware of it.
His dtilt actually outranges both grenades and our ftilt1 I'm pretty sure, but it really should never be the case he gets to space perfectly against our ftilt.
I hope it helps someone.
But everytime i see a vid of seibriks mk I'm not impressed at the same time : | I must just be hating for no reason.
