Follow-up to "Trollhunters" and "3Below:" all of these are subtitled "Tales of Arcadia," and "Created by" Guillermo del Toro. Which I have to admit doesn't carry as much weight with me as it does with most (I wasn't a fan of "Pacific Rim" or "Hellboy 2"). But yes, I watched both the other series right through.
This opens after the events of "Trollhunters." It's harder to place in relation to "3Below:" probably after it as we see Krel is in Arcadia but we never see Aja (Wikipedia says it's after). And this is the shortest of the three: "Trollhunters," the first series, was three seasons, "3Below" was two seasons, and "Wizards" is only one season (ten 23-minute episodes) - although Wikipedia suggests we're to expect a follow-up movie (and they left some dangling details for it).
Our hero is Hisirdoux "Douxie" Casperan (voiced by Colin O'Donoghue) who (inevitably) lives in Arcadia - but turns out to be Merlin's apprentice. And after 900 years of apprenticeship, he's finally called on to do something more than mop floors. He's accompanied by his talking, flying cat familiar Archy (Alfred Molina), and teams up with some of the previous defenders of Arcadia - initially Claire Nuñez (Lexi Medrano) and Steve Palchuk (Steven Yeun), but that roster fills out over time.
I found I was really tired of the Palchuk schtick - shrieking in fear, making stupid comments, magically fighting well when it's convenient to the plot, etc. And Douxie is ... a fairly good character, but not as compelling as Jim Lake in "Trollhunters" or Krel and Aja in "3Below." I'm also tired of their perpetual plotting practise - out of the frying pan and into the fire, pretty much every episode. Definitely the weakest of the three series.
SPOILER WARNING, stop reading, blah, blah, blah.
Postscript: An interesting thing I realized about this "tale" is they killed off pretty much every adult they introduced. Nobody's parents were involved this time, but passing-the-torch was pretty terminal for the adults in this series.