no persona:
Fair hit 1 > jab > jab > fsmash
taken from void's recent joker guide, highly suggest you all to check it out
That fair 1 has to be on an aerial opponent to drag down. It's a jab lock set up.
Also for fair 1 to knock the opponent down they have to be at about 80%.
You can put them into the air with a fair 1 and drag down with another fair 1.
So realistically it should be fair 1, fair 1 (on aerial opponent), jab, jab, f smash.
I labbed out the set up the other day, it's crazy good.
I've already managed to hit it in a couple friendlies.
It's important to note that while fair 1 won't knock down an opponent below ~80%, it will drag down and allow a free follow up like the up air drag downs.
However, I feel like fair 1 drag down set ups are better than up air drag down set ups in many cases.
You can convert on a spaced fair 1 and get the grab off of that.
It's also less DIable and will likely work on floaties too.
Oh and the set up works with persona too.
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Other set ups include:
Fair 1 (on a grounded opponent) -> up smash.
Gun -> gun dash gun (knocks down) -> gun dash gun (locks) -> f smash
The gun lock is really tight though and gun doesn't start knocking down until around 100% for mid-weights.
Spacing it is also kind of a struggle because 1) you can hit them off stage and then it's ruined 2) you can fail to space it properly to follow up with such a strict timing.
You can also use gun to lock from a fair 1 drag down lock, but it makes the timing more strict for the sake of a bit of additional damage and it's probably not worth it.