You can counter Rumble V with Gravity V or C because they are stuck in one place until the move is finished. This logic also applies when they use Dough V, and Portal X Spirit V, Ice, V (if the user is not careful). Essentially, you can counter any move that makes them stuck in place for a long time.
Grav cane pull (Z), Serpent bind (x), Grav V then Grav X quickly, Melee moves or serpent Z. Not sure why he's using those goofy stats though. If you can, get strong grip on serpent bow and Grav Cane.
check the combo video but its Gravity cane z then serpant x (if your fingers cant move lightspeed to do next moves) then really quickly gravity v then x (hold) I recomend cyborg so no instinct dodging then you can do gravity cane x then gravity cane z (if you have ghoul) then gravity z if they are still alive then repeat.
I got a server where 60mils teach PvP I'm not saying you need a teacher but I'm saying we can help you become the true definition of inescapable but that is your choice to make