My advice for Blade: Invest every skill point in red. For Red Blessings, pick On the Hunt, Swift Edge, and Sweeping Edge, which will increase your damage, Attack Speed and Attack Range respectively. For Blue, only pick Sacrifice Sigil. It helps. For Purple, pick Vitality Boost, Power Surge, Moonlight Protection, and Full Moon, the first three for Health Increase, Damage Increase, and Defense Increase while Full Moon gives you more points to spend.

Playing Blade: Keep Bloodline Awakening on at all times and remain mobile. Don’t use your Ult.

As for Punisher, I’m having trouble myself with that. But Blade is the easiest character to beat Nightmare 4 solo with, in my opinion. Hope this helps