I kinda have the feeling that Arthur is gonna be one of the last ones to find out. =/
So i would say Gwen or Morgana, but i'm picking Morgana for some reason. lol
At some points, i really thought that Morgana was gonna find out.

Based on the beginning of the season I would've said Gwen because they were closer back then.
But, as of now, if someone's to find out about Merlin's magic I think it's Morgana.

I thought she already found out?

^ No, she doesn't know yet. =)

Ya it would kinda suck if Uther found out...lol

Yeah... Merlin and Arthur were in a cave, trying to get rid of the monster that was poisoning the water... Merlin performed magic to help him and later Morgana said something like, "I saw what you did back there but it's alright, I won't tell anyone"

*sigh* Maybe I'm just imagining things...

I think Morgana will find out first seen as she is a magician too and that she may have her suspicions allready.
Arthur is too blind to even consider it and Gwen isn't that close to him anymore, and yes Mallory101 it would TOTALLY suck if Uther found out ;)

I have a funny feeling Morgana will find out in Episode 2.03!!

I almost thought Morgana was going to find out in 203, but I kind of hope Gwen finds out first and then has to keep it secret and she'll be all worried all the time and stuff.
Though part of me hopes that, on some level, Arthur already suspects something, but it's kind of a "don't ask, don't tell" thing going on.

Either Arthur or Morgana. If Uther found Merlin may not have head on his shoulders. Just Arthur out of randomness.

Okay, I was wrong. I think a lot more people will find out next series, because otherwise it will get really tedious.
Bradley James was saying that he thinks (especially in 2.13) that Arthur is starting to join the dots and realise that Merlin is magic. I mean, he could've seen Merlin talk to the Dragon? He may have seen Merlin do some spell a LOT of times. I reckon Arthur will ask Merlin whether he is magic, instead of Merlin telling him. Then it would be cool to see Merlin spill about everything he has done to do with magic to save Arthur’s life, and it would be depicted as a HUGE montage. That would look really cool in that episode.
I reckon when Arthur does know, he will keep it a secret, but will be more kind to Merlin, for fear of being turned into a toad or some ridiculous fear like that.
Morgana will know, because Morgause will probably tell her. Morgana may come back and Merlin to come on their side in defeating Uther. Merlin may be tempted to give in, but at the last minute refuse.
I think the thing that no one will find out about for a long time though is Merlin's destiny. It is something too heavy to talk to Arthur about, and Gwen would not simply understand.

I so agree knight_princess

morgana i think

I agree with knight_princess completely! Also, Morgana has her own magic, so Merlin might feel he can confide in her at some point (unless she turns evil and tries to kill him...)

I pretty sure it will be Morgana.. But I don't think it will be Morgause will be the one to tell her. I don't even think Morgause knows since she called him a servant boy in epi 12... But maybe Mordred will tell her ?

I reckon Mordred might tell her. But I really hope Arthur finds out =D

because she is smarter than him, she'll figure it out :)) I want Gwen to know it too and to learn that he poisoned Morgana.

i would LOVE it if Morgana found out, then she would be focusing her attacks on Merlin and have some epic battles.

If she doesn't find out first, I will complain unofficially to the BBC.

hahahahah Uther found out first :'D