anyone know if minus res still applies after the monsters are taken to 0 res? or is the minus res applies before this passive (which in this case could make minus res irrelevant in some cases)

it doesn't say it takes their rez to zero, it says it ignores rez abov zero. So since it doesn't modify it, you necessarly check rez after they are calculated.

so after the taking res to 0 i calculate the minus res from there? ( forexample, if it ignores the res above 0 and i have - 30 res, monsters take -30 res dmg nomatter how much res above 0 they originally had?)