Once you get to the checkpoint, an in-game tutorial will teach you how to do the Ground Shaker. You have to do the Ground Shaker to continue and then you’ll instantly have to fight the Shadow Guard. What I did was wait for him to do his slow swinging attacks and once he got pretty close I’d jump over him power punch him a few times and back away. I continued this until he was defeated. Also watch out for his Ground Shaker attack. Just jump straight up to avoid.
He pretty much has two health bars. Once the first one gets down about halfway a few other enemies will show up. They can easily be taken out. Once the first bar is depleted, his helmet falls off and the second health bar takes no time to eliminate.