Se = My name is Sebastian. Ga = Cat in spanish is Gato (I really like cats). Co = My uncle always calls me "Klo", so I wanted to put that in the name.
However, Segaklo sounded a bit weird so I changed the K to a C.
But I kind of forgot to type the L so instead of Segaclo I ended up with Segaco.
Found out what happened a month after I registered on a random website (I never look at my username).
Decided that it was better and kept it like that.