In the country of Valiante there are monsters called Horrors who prey on people and people who hunt these monsters, the Makai Knights and Alchemists. They face danger not just from the monsters but from the king and his advisors who are mistakenly leading a witch hunt to kill them all and have nearly wiped the knights out. Leon's parents were a knight and alchemist and when his mother is killed his father Germán is stuck raising a son whose as hot-tempered as he is easy-going and consumed by the flames of revenge. Meanwhile, the similarly-aged prince of Valiante Alfonso has started to realize that there is something wrong with the advisor Mendoza who always has his father's ear....
It's hard for me to talk about Garo without overly nitpicking at it so let me get those, relatively small complaints out of the way. This is a series where, like in many other tokusatsu and magical girl shows, ordinary, random people are turned into horrible monsters often without making an actual choice and there is no way to save them. I'm not fond of this trope, I think that it's inherently weak storytelling and whenever it happens without a choice (which is the case at least half of the time here) it feels as if the side characters are flatter than a pixel, not unfortunate tragic victims like the show tells me I'm supposed to feel. This series also does not hesitate to kill off various important characters throughout it's run and had such strong death "flags" that I didn't expect any of the female characters to make it through to the end. It treats them [side characters] the same way it does the male characters but I always had a lingering worry that they would be fridged, that the writers were either unaware of the cliche they were following into or just didn't have the creativity to write their way out of it.
Thankfully the series isn't nearly so dire as that may sound, it's a very solid hero's journey that, like many others, doesn't do as well when it's focus isn't on it's leads (I'm calling Alfonso and Germán leads as well as Leon given the amount of time their own stories get when split up from each other). Leon has the more traditional hero's journey than Alfonso since his is the one we see from start to finish and he's the one who has the farthest to grow. My other big quibble with the series is that it really takes too long to have Leon make progress in the early part of his journey, while not a jerk he's reckless and impulsive to the extreme and it takes until about halfway through the story for him to finally cool off and this isn't due to the accumulation of events or time, it's because of an event that shifts his entire life. After that it seems like the series is trying to make up for lost time as it races through the other stages of the journey (such as "re-evaluating your reason to fight"), especially since by this point Leon, Alfonso, and Germán have split up and the series is now trying to cover three story threads instead of one or two. It is a good story when it gets moving however; I do also have complaints at how a hero's story never lets the hero "retire" to live a simpler life (unless they're the older, side/mentor character in another person's story) but much like the potential fridging that was what I expected. To talk about those side characters again, for the characters that the series spends a lot of time with (like Ema, Ximena, and Lara) they're as fleshed out as any male character who spends a similar amount of time on screen. When the series falls into a predictable trope it doesn't defy expectations but when it has a chance to work on the smaller details it performs magnificently.
Also magnificent are the fights, the CGI in this series wasn't a really great idea but the all 2D fights we have (pinnacling in one between Leon and Alfonso three-fourths of the way through) are really great looking fights with smart choreography and the directors/storyboarders have clearly thought about how both the characters and the camera should move. The designs for the series (especially those CGI suits of armor) are hit or miss however, I was okay since they never looked overly weird but the very few times the characters are in full, bright light you see that there were some interesting color choices made. Studio MAPPA's other Fall 2014 anime Rage of Bahamut had better costumes and sets in my opinion (although, considering those were already existing designs the praise doesn't go exclusively to the adapting staff) but story wise I think this was the far better show. Bahamut started to fall apart in the second half and just barely pulled itself together in time for the finale but Garo only gets stronger as the series continues. I didn't enjoy it so much that I want to dive into the tokusatsu Garo series but I can also say that you can come into this series completely blind and still end up really enjoying it (it appears to be getting some kind of continuation which makes me hesitant but I'll certainly check it out). For anyone who cares to, it is also licensed by Funimation and can be found streaming on their usual venues.