Warning: Full reviews contain spoilers for those who have not yet seen the episode. Updates will be made as more reviews come in.
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Den Of Geek "It is the emotionally charged moments, of which there are many, that really drive this story forward. Michie's story could really have benefited from a second part, with more time spent exploring the first real challenge to Arthur's kingship and more screen time given to Lindsay Duncan. It's a great story that continues a season that seems to have been set up with the future well and truly in mind."
Dan's Media Digest "...For the most part "His Father's Son" gave us a story I don't recall being done before on Merlin. Some of its ingredients were familiar, I suppose, but it was just great to have a story with something weighty on its mind."
Daemon's TV "Arthur’s adjustment into life as a king is, I think, going to be of significant thematic importance to this season. In this episode we get a lot of the darkness I love about Merlin...The humor is mostly gone and the episode is all about Arthur battling with his inner demons."
Dork Adore "This week’s story does comprehensively deal with a complaint I made last week about the ignoring of Arthur’s new crown. So, is it as good as I hoped? In this episode, young Pendragon confronts all the issues."
Critictoo "Arthur faces his new responsibilities as the king who gave birth to a major conflict in which the lives of his men find themselves in the balance. Morgana takes the opportunity to provide support to opponents of the new king of Camelot."
Digital Fix "It feels like they’re trying to make Merlin a more grown up version of the fun and frolicking of the first few series. It works most of the time, but sometimes it gets a bit awkward and clunky. This episode, whilst being very enjoyable, was definitely an example of that. Whilst I love watching it and am glued to the screen, it feels a bit like something is missing."
Sci-Fi Pulse "This episode was all about Arthur’s first real test as a King and provided some great scenes for Bradley James, who really rose to the task. It also provided Morgana with her longest period of onscreen time for this series, which is always a good thing as far a I’m concerned."
Simply TV "Episode five is a big improvement on last week's episode; a more ensemble piece in which all the characters get something of substance to do. This episode in my opinion probably would have been better and more effective shown after the death of Uther in episode three, as we explore Arthur's (Bradley James) new-found role as King of Camelot and what kind of King he is to be."
SFX "Arthur feel he has to show strength so people respect him; it’s a very grim opening to the story...Bradley James does a great job of making Arthur look troubled following it."
Radio Times "One of the truly impressive strings to Merlin’s bow is the ability to attract classy names. Charles Dance, Miriam Margolyes, John Lynch and Frank Finlay are just some of the thesping titans to romp through the fantastical landscapes of Albion. The serene Lindsay Duncan is the latest to join the Camelot club."
Geek Syndicate "The lesson-of-the-day was a bit heavy-handed but overall, nice to see Arthur progress a bit on his path to truly being the King of Camelot."
Digital Spy "We feel like it's time for Morgana to discover Merlin's powers - it'd certainly make for a compelling new twist and could provide plenty of material for storylines..."