I don't know if this is still a thing or not...
but when I had a character in the early Mabinogi days in KR server, servers had age restrictions. For example, Lute and Wolf were 12 and over, while Harp was 18 and over. Not sure why they did that or if they still do it.
Another thing to note is that some Koreans might not exactly be too friendly with foreigners, especially if you don't know Korean, although I'd assume this is mostly not the case. And also, little Korean kids that play this game, or called 초딩 in Korea, may be a bit of a bugger to you, but then again, I guess that's the same with any country.
Also, I don't know why no one mentioned this in this thread. But this is how KR server registration works. First of all, you'd have to get your Alien Registration Number. This is an equivalent of Korea's Resident Registration Number (주민등ë¡ë²ˆí˜¸), similar to Social Security Number of the US. Once you have the access to your number, you're now recognized as a foreigner staying in Korea. Second of all, you'd have to use I-Pin. When you try to make an account in Mabinogi, it should prompt you to register with I-Pin account, which you can confirm your membership via mobile devices.
Quote from Kapra;1260068:
You can move pets/chars over? Or do you just mean recreating them there?
Yes, KR servers do allow (or at least did, I don't remember) to move your characters. Your stats, skills, items, everything. It's a wonderful feature that NA Mabinogi still hasn't done for some odd reason.