I got to level 15 and then decided to double-check. You were right, this was a guest account. I'll be honest though, I lost my Taiwan ID and I had to remake another gash account (thank you Yahoo for deleting mails past 2008 ugh), with a different ID. I then used this different ID to upgrade my guest account to full account (this time I saved the info on Notepad).....but I noticed something irritating.
If you upgrade your guest account to full account, you will always have to sign in with the @whatever.com email address. If you decide to just make a full account from scratch, you'll then get a user ID without the @whatever.com at the end. I prefer usernames other than email addresses, so now I have 2 different Elsword accounts (both full) XD
I don't know whether it's my imagination or it's just pure luck, but I seem to be getting more luck with boss drops in my full account than my prior account as a guest. Interesting.
If you already have a Taiwan ID from Taiwan GrandChase, feel free to upgrade your guest account to full if you want. My TWGC account is 2 years old, I would've never used another ID to for Elsword had I not lost that email T~T;;