Yes, someone made-up the design, either themselves or with the help of an artist and then they "own" the character, hence why it's original! c: Haha, I am not really good at lingo either, I'm 30, so I don't use a lot of slang in my day-to-day life anyhoo. But I try sometimes. I browse this site called imgur a lot and I guess that keeps me in the loop lol.
XD this face is like a really happy person with their eyes closed and their mouth wide open! Like in laughter! Yes, OTL! Haha, I didn't know what that was either at first and I had to ask the person that used it with me ; v ; I really like using japanese emoticons too because they're super cute :>