Fighting Moloch without taking damage is insane, but you can cheese it because it says damage and not hit, meaning if you can get hit without taking damage then you're fine.

First, obtain the "Legion Shieldbearer" creature core up to level 3
This can be obtained easily three ways:

• Killing the boss of chapter 14
  
• Playing the Arena mission "Hell Brutes"
  
• Getting lucky when buying Vulgrim's "Creature Core Pack- Redwaste (Rare)"

Second, set difficulty down to Casual, this will easily let you take a hit or two.

Third, learn his attacks and dodge them properly.
You would have to do this anyways, but with the previous steps you now have room for error.

• Play as Strife
  
• Crystal attacks can instantly go through your shield
  
• When his sword combo gains a third hit, start dashing behind him on the third swing.
  
• Switch to War to instantly refresh your shield

First and foremost, if you're stuck at 66/67 then you're probably missing the Leviathan core, you have two options for obtaining this core.
You can abuse level geometry to skip the entire thing or you can do it legitimate and navigate your way through a long maze of precision platforming.

This is easiest to do with a controller, I don't know if it's possible without one.

1) Play as War

2) Rebind Jump to the same button as War's primary attack

3) Navigate yourself up the rocks next to the Trickster Door in the Void, above it you'll find a flat area with a ledge, on top of that ledge is the Leviathan core.

4) Stand here

5) Spam your Jump/Attack button while moving forwards
Eventually you'll find a sweet spot that will bring you over the ledge and to the Leviathan Core.

Once you somehow manage to get past all the dogs without killing them, go here and neither the dogs nor the houndmaster will be able to attack you.


Switch to Strife and just shoot the Houndmaster with standard ammo because it's the only type without some form of ability to hit multiple targets.

You may have to kill a few dogs for the Houndmaster to come to the front, so any that you don't kill along the way there will help you greatly.

In case you already have the Leviathan core, here's a simple check list to make hunting down which core you need easier.
This doesn't include progression bosses because you get those guaranteed.