If your at hell cows you should more than likely go to nmare cows to level up your merc... It wont die as much cuz for 1 nmare cows are weak and 2nd.. you should be able to kill them before they do to much damage
and also, u say u just buy a merc and go straight to hell cows, well, wherever u buy a merc from, they will die pretty quite in hell cows.... but, in my books, the best place to lvl him/her is in a bloodrun game...
with on, or two ppl in
nah u8 go into nm and u give him/her good mf gear and good gear so he has mf and hes good and when he kills he gets your mf+his so u gets more mf than u and u sheild him and let him kill plus he lvls up!
No way, the best way is to do mephisto runs in nm or hell, depending on how good ur guy is, then once he or she is high enough lvl i go rush people for free and get 1 or 2 or 3 lvls per act depending on the lvl, my merc is lvl 91 (maxed because my barb is lvl 91) and i lvled him a lot when rushing!!