It's an incredibly poorly designed boss-fight, there is really only one way to beat him and once you've figured out the pattern you'll likely do it without taking damage.
It's pattern memorization at its most extreme.
Here's the gist of it: Block until he charges his red attack, then counter(timed block), he will stumble back, then you can hit him 3 times. Then just repeat that until he's dead.
The most dangerous part of this type of boss battle is boredom, because repeating a pattern like this for 3 minutes straight is incredibly uninteresting!