1. In the OTC we generally identify VFIN,VNDM and BMAK as dilutive market markers and CDEL and NITE and ASCM as shorting MMs. Do those roles ever get reversed.
CDEL is as bad as VFIN for diluting, however he is more likely to be retail than VFIN.
Keep in mind, I have personally been routed through VFIN randomly so do not discount that it could be retail
NITE also a POS, but is more likely to be retail than dilutor, but is still fully capable of killing a stock
ASCM you can avoid, unless it looks like it's a rally and they are covering and pushing the ticker up, but that's a more nuanced read of the L2.
2. Why do dilutors or shorters use specific market makers to do their 'dirty' work
Keep in mind, toxic note holders and short sellers are partners -- and essentially the enemy of retail
The shorts know exactly when notes hit because they actually read financials and know when VFIN is going to show up
* May your trades turn out well and bring you profit - Good luck *