I went to where it’s marked on the map but can’t find it

I think the video mentions you have to go there at night, as that's when the Knight spawns

The map is wrong, he is on top of the hill above that fat road area, near the big building.

the map is wrong, teleport to warmasters shack, take the road north till you cross under the giant highway and see the collisium in front of you then take a right and follow the right edge of the giant highway east till the part where it is collapsed and take another right over the rubble south-southeast and you should see a ruin ahead of you with a cliff edge to the east, head between the ruin and the cliff edge and you will see the knight ahead of you time of day is unimportant (he's pretty much directly left of the deathtouched catacombs marker on the map on the cliff above)

For anyone having trouble finding him, he is not in the camp. He is in the high cliff above near the edge. You have to go around through the forest and uphill

the marker on the map is slightly off, this drops off a mounted non-boss knight slightly north east of where the marker is on the edge of that cliff.

This costs 40 FP to cast, lasts about 45 seconds, and increases damage by about 10% based on some quick testing.

duration seems to be ~45 seconds

It's at the edge of the cliff. You need to go on top. The coordinates are a bit off. It should be around (-175.9375, 104.54688)