Boreal Outrider Knight Knight Guide – Dark Souls 3 Wiki Fextralife
The Frost Knight or Frigid Knight is an extremely difficult miniboss to solo. It is ultra agressive, hits hard and is simply relentless. Do not worry if you die several times before you get him. That is to be expected. The first thing I want to mention is his Frostbite debuff. This is new to Dark Souls, and if effected, will drastically reduce your Stamina recovery speed, all but killing you. However, it doesn’t play too much of a role in this fight as you will usually die from damage before the build up is high enough to fill the bar. The Frost Knight “usually” hits in 2 hit combos. I say usually because there are exceptions, but if you stick to that rule you will be able to complete the fight taking relatively low damage. Never attack until AFTER attack number 2. He has a special attack where he breathes frost into the air. If you get hit by it you will most likely gain the Frostbitten debuff. It is easy to read and a great opportunity to hit him or heal if you need to. Be careful WHEN you heal. There are very few opportunities where you can actually pull off a heal (even when you think you can, you usually can’t).
Make sure he is mid combo, not at the end of a combo, when you heal or you will pay for it. As with the Dancer fight, the key here is Stamina management. If you try to block both attacks most of the time you will be guard broken and it will get you killed. The best thing to do is block the first and then try and roll through the second or simply step left or right so the next attack misses leaving you free to attack.
You will only get 1 or 2 attacks at most, if you try for more, you will most likely get yourself killed.
As found on Youtube