Chaos Advent basically my favorite type of boss. Dude that will hold you down and not let go until you take a deep breath and make an effort to learn the mechanics of the game, and his set of moves.
I had been walking into this so far as an unga bunga brawler - which TBF is not untrue for most of the mobs - but a good boss battle was enough to make me rethink Cancelling, Parrying and taking my time instead of punching wildly.
Tiamat was basically that again but for magical attacks. Simply superb. What an amazing action game that only makes me hate more how the FROM model of having the most sluggish combat has become the norm.