I seriously need help in that mu. Im gonna play billy and grind it out tomorrow after work. The last long set we played, I beat him but I still wasn't convinced. Its like grundy is the perfect counter to my style of play
I had a discussion about this MU a while ago somewhere in the NW section but I don't remember where. I'll give you the TLDR on how to win it.
Both stances do well, as long as you understand what to do in them.
In escrima:
B2 is a really great button, has throw invulnerability if you time it just right, and has decent range so it does well in the space where Grundy wants to play ground game.
Watch for him doing walking corpse through your b2. If you see he's trying to wc, do b2 into flipkick and you'll cross his inputs up, so he won't get the cancel. You can whiff punish it from behind him or your flip kick will hit.
Wing dings are a good option against Grundy, but aren't great. He can walk through them and if you try to do delayed mb on them after he blocks he can walk through and punish it.
You're normal pressure against him works just fine, so nothing has changed besides the fact that he can try to walk through some gaps if he times it really well.
Staff:
Stand 1 into ground blast is still a good option, but be careful since he can WCC through it. If you see him doing wcc in between stand 1 and ground blast then do jump back 1 to either punish the throw attempt, or force a block after he walks through. If you see that's he's always walking through, do stand 1 into staff spin and he will be hit out of wc.
Jump back 1 in general is really strong against Grundy's options. Even if he tries to preemptively air throw it you'll either win or trade as a worst case scenario.
Stand 2 is throw invulnerable, so jump back 2 into stand 2 will beat any attempts at raw walking corpse to trip guard a jump back.
Play footsies mostly with stand 1/b1 in this MU. He has to be on point with his whiff punish to deal with these options. He can stand outside of your stand 1 range and try to do raw swamp feet mb to catch a stand 1 but it's super desperate of him.
Ground blast is a good option against Grundy's approach as long as you watch his meter and don't eat too many mb swamp feet as a response.
General:
You can mb b3 him if he's doing a super basic mixup with 112 into swamp feet/cleaver but you probably know that.
Get used to reacting to b1 on reaction if you can. It might be hard to do online though.
Backdashing Grundy's mixups is really good since most of the time he is trying to cancel his normals for mixup, and if they never connect he won't get a chance to.
Mb b3 is also really strong in this MU since Grundy's options are slow and generally single hitting. He can use his own armor to get through this, however.
And just in case you needed them, here's some videos of the MU:
