Merlin returns to Syfy for a fourth season on Jan. 6, and while Colin Morgan admits his title character remains somewhat awkward as he continues his path to becoming the greatest wizard of them all, Merlin is becoming less naïve, more grounded and a lot wiser.

Relatively unknown when he was cast as Merlin in 2008, the 25-year-old Irish actor made a name for himself with roles at iconic English theaters like the Young Vic (Vernon God Little) and the Old Vic (Todo sobre mi madre).

Now, after four-plus years on the BBC fantasy series, Morgan says he continues to learn from Season 4 guest stars like Phil Davis (Vera Drake), Gemma Jones (Harry Potter and the Chamber of Secrets) and James Callis (Battlestar Galactica).

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I spoke with Katie [McGrath] yesterday, and she teased that the two of you really get after one another in Season 4. Care to corroborate the story?

Colin Morgan: Yes, there is a big connection between Merlin and Morgana this series, and it's a very interesting one because Morgana learns of this old sorcerer called Emrys, who is actually Merlin because Merlin can now transform into older wizards. And that's the form that she recognizes as her doom, as her downfall, as her death. But Merlin doesn't realize this. And neither does Morgana, so she has this huge fear and this huge mission to find out who this Emrys is and to destroy him, but again, she doesn't know that Emrys is Merlin. It's a big, big part of this series, and it's also kind of a subplot to what's going on.

Merlin and Morgana certainly meet head-to-head on several occasions throughout the series, too. And having gone through what they've gone through – Merlin trying to show Morgana the right path and her very much taking the wrong path – there's really no love between them anymore. Whatsoever.

Merlin is famously awkward around fair maidens, and he is no stranger to embarrassing himself around Camelot's royalty as well. In Season 4, do we start to see a more capable Merlin and perhaps even someone we should begin to recognize as Camelot's great wizard warrior?

Our characters always had this kind of growing-up feel, particularly for Merlin. In a way, he's got the slowest-burning journey. He has to put himself last, after everyone else. He's been thrown into this world, with his destiny of ensuring that the kingdom reaches its full height, that magic is restored to the kingdom and that Arthur becomes the greatest king the land has ever known. Only then can Merlin be who he is going to be. He really has to put himself last, which is maybe why he hasn't developed as much as the others but he certainly is becoming a lot more mature. He is becoming a lot less naïve, he's wiser and he's more grounded. He is also developing a better understanding of who he is supposed to be and what he's supposed to do.

As we enter into the fourth series, we really see him grappling to keep hold of his relationship with Arthur too because in a way, things happen and things come to head where they are slowly growing apart and that's a big, big challenge for Merlin this series – to really hold onto what he has.

Some of the best parts of Merlin are the banter between Merlin and Arthur. Despite all these big-budget, epic battles coming this season, is there still the same level of playfulness between the characters?

There's definitely still that banter-filled relationship between Merlin and Arthur. As dark as the show goes, it always balances itself with some great humor. It really makes it interesting when the writers try to balance it out that way. Fans of the relationship and the banter between Merlin and Arthur really should have no worries at all – it's all still there.

How about yourself as an actor? We've talked about the growth of Merlin, what about the growth of Colin Morgan?

That's been one of the best things about the series is that it takes eight months to film one series, that's eight months in front of a camera, every day, working on a complete variety of different scenes with fantastic guests artists coming in. The actors that we get coming in as guests, we learn so much from them and as a young actor, I try to absorb as much of it as I can. And gain as much as I can and learn as much as I can. It's important to just keep an open mind and not be afraid to make mistakes, no matter how much you know your character and are comfortable with the material. You can't be afraid when a new director comes in and wants to try new things and try new directions. That's exciting and that's challenging. And as an actor, you have to relish all that.

Scholars estimate Arthurian legend may be more than 900 years old. Do you take that to heart when you are starring as Merlin in Merlin, which serves as a gateway for so many new viewers, including young children, or is that too heavy a burden to carry?

I read quite a lot about Arthurian legend at the beginning of the series. Certainly the first couple of years, I kind of exhausted all the material – the Tennyson, the Mallory – really anything with "Merlin" in the title, I read. I think no matter what genre you work in or any material, it always helps to have a little bit of knowledge of the area that you're working in. And so I now have a definite appreciation for it. What it made me realize was that the legends are legends and they're popular because they are retellings, they've been retold, they've been added to, year after year, century after century, they've grown, they've been adapted, they've been retold again through word of mouth, through writings, and now we're a part of that same legacy, that same thing that's been happening for centuries, retelling the story our way. And I think any fan of Arthurian legend will appreciate that.

Historically, Merlin has a long, white, flowing beard. How's your facial growth in Season 4?

[Laughs] I actually have a beard right now. And that's only because I've stopped shaving, because I have to shave every day when I'm on Merlin, so I just stop when I'm off, which is a big relief. Whether or not I will be able to keep it for the new series, Season 5, you'll have to wait and see [laughs].