Ooooooooookay, I have a lot to say about this.
First of all: this can't be anything else than a 10 out of 10.
Yes, I have to admit, while watching the first episode, I really didn't know what to think about it. Just because it is sometimes soo much over the top that it seems unrealistic and ridiculous. But against my better judgement, this style grew a lot on me and even became one of the reasons why I fell so much in love with this show. This humor made the gruel scenes bearable and I enjoyed each of Vincenzo's & Cha-Young's wins against the antagonists way too much. I also can't tell how often I had to laugh out loud or said "bro you're dead meat now", everytime the villains did something stupid.


Careful, spoilers ahead!!!

Now to the characters, starting with the bad guys. And ladies.
I LOVED how they were revealed and you couldn't tell right from the beginning, who was one of them at all. Of course, our main baddie was quite the surprise, but I wasn't even sure about lady right-hand in the beginning. And then there that a**hole lawer we thought we liked, or Cho Young-woon, the Geumga Plaza manager, who was suposed to be a friend. An even better twist, that he changed sides again and ended up fighting for Vincenzo.
The same goes of course for our baby, Jang Han-Seo, who was a bit of a pabo, but an adorable one. I really loved his character development and it was so sad, that he had to die. But, it made sense for the history, everything else would have been weird. He betrayed his brother and we know he would punish him for that, there always has to be a loss at some point. At least he protected our main leads and died as a dongsaeng to Vincenzo, that was really heartwarming. Also the death of his mother, Ms. Oh was expected and I'm sure she knew that he was her son when she died.
I loved all of the Geumga-Plaza family, every single one. Even the nutria, who was also one of the villains in the beginning. The same with our detective Ahn Gi-seok, he was just too funny. I won't write all of their names down, but I have to add that it was a pleasant surpise that Mr. Lee actually survived. Two very small things tho: I would have loved to see Vincenzo just onces as a godfather of baby Dae-ri, and once enjoying the food of our cook Toto. What a shame...
Coming to our Protagonists now.
They were the best, like, at all. Not good people, by all means, they had to become monsters in order to punish the devil, but they had the greatest chemistry, great arcs and character development, were a little crazy and just funny. I loved the very-slow-burn and that there was no focus on their romance, but it developed naturally. From kind of enemies to friends to lovers, the perfect, hilarious (and dangerous) couple.
I'm sure I'm gonna rewatch that show at some point, this is as great as The Devil Judge (just not that dark emotional, but instead on the lighter, funny side, which is not bad, just different.)