Ophiuchus

Ophiuchus (Real name: Orville) is an AstroLOLogy fan character. He is a silver-haired snake-bearer who wears a black shirt, a silver vest and purple pants. He has a pet snake named Ollie. He is unofficially the 13th main star sign. This fan character is made by StarRion20 on DeviantArt.

Description
He wants to be cool and very serious about himself, even when he has a lot of things in his mind. Along with his pet snake named Ollie, he has a friend when he is doing something cool. He imagines himself if he was part of the star signs, but he doesn't want to mess up the cycle.

Real Life Counterpart
Ophiuchus has sometimes been used in sidereal astrology as a thirteenth sign in addition to the twelve signs of the tropical Zodiac, because the eponymous constellation Ophiuchus (Serpent-bearer), as defined by the 1930 International Astronomical Union's constellation boundaries, is situated behind the sun from November 29 to December 18.

The idea appears to have originated in 1970 with Stephen Schmidt's suggestion of a 14-sign zodiac, also including Cetus as a sign. A 13-sign zodiac has been promulgated by Walter Berg and by Mark Yazaki in 1995, a suggestion that achieved some popularity in Japan, where Ophiuchus is known as Hebitsukai-Za (蛇遣座 (へびつかいざ), "The Serpent Bearer").

In sidereal and tropical astrology (including sun sign astrology), a 12-sign zodiac is used based on dividing the ecliptic into 12 equal parts rather than the IAU constellation boundaries. That is, astrological signs do not correspond to the constellations which are their namesakes, particularly not in the case of the tropical system where the divisions are fixed relative to the equinox, moving relative to the constellations.

More info Here.