Rivers of Blood or Nagakiba with double slash or both? and if so which one in right hand?

so i have nagakiba and im abt to get rob,curretnly i have 40 dex and 10 arcane with bloodflame blade AND DOUBLE SLASH but im thinking of gettting rob,upgrading arcane to around 30 or 40 and then ditch bloodflame and powerstance both but what do i do then? do i use the aow from rob? or just the normal l1 to cause bleed?

so for short im asking if i should rob or nagakiba or both,and if both do i l1 or l2 and if i l2 which one in right hand and if its nagakiba right hand then what aow? curretnly using double slash