The idea is that the Vigil can only be hit while staggered. To stagger it, you need it to lunge at you so that it ends up at the edge of the platform. The only way to dodge its lunge is to use your phase ability. If it hits you, you tumble to the ground, and the window to hit it back closes before you can get up.
Striking it while it circles you causes it to leap out of the way and counter-attack. The counter-attack will be a lunge, but if you manage to strike it afterwards, the next attack has a 75% chance of being a vertical crescent strike, to keep you on your toes.
After one third and two thirds of its health is depleted, it shoots horizontal crescents at you. These must be avoided by jumping - the phase won't help. That's the game's language: red and electric = no phase.
One little thing I kept for the adventurous or for speedrunners: You can get to this boss without grabbing the phase skill first, but the idea is that you should go get it before facing the Vigil if you don't want a bad time. There *is* one way to avoid the lunges without the phase, though, and that's by getting off the platform. If you're fast, you can get back up and get a hit in before it recovers.
Mind: This is the first boss in the game, and it's not a soulslike, haha. I want it to be relatively easy, but not dull.
