I killed him in 5-8 min by self defence and saving.I was a kamikaze that almost died but alive. Marcus dead. My wishes come true. That was THE HARDEST FIGHT that ever seen.Even other bosses was ez but this was hardest.Good luck
For me I choose to balance it but when it comes to character with build in stopping power or using shock ammo is best to use weapons with high rate of fire since stopping power act as a mini stuns to the enemy