RuneTale Sans is created by Your_Average_Glitch. He looks like a typical Sans, apart from his eye lights which both hold yellow and blue pastel combination, he wears a red cloak which is  a magic deflector, but physical weapons can damage it. On his left cheek he has a solar cross symbol. RuneTale Sans wears a grey sweater with grey, black and white shorts and black and white converse, and on a necklace he wears the rune. The rune is a stone that is remarkably powerful.

RT Gaster has been trying to contact different Aus but contacted a creator (Also known as us) instead. They talked, and The creator gifted him the rune which held a small sliver of the creator's power, Gaster also learned of his future demise, so he created sans (there is no Papyrus in this AU) to be the sole guardian of the rune.

Gaster was fired by the King and everyone thought he was crazy when he tried to tell them of the creator. Sans was home schooled and kept up inside of his house or Gaster's personal lab. All the children and their parents rejected sans which led him to have phobias of being alone, being forgotten, being useless, being hated by everyone, etc.

Chara, which in the Au is a demon, was drawn towards the magic of the rune, so they fell down and was met with Asriel, to which they killed. Gaster and chara fought, Gaster killed chara's physical body, but the actual demon remained, but could do nothing. Gaster later died during an experiment, 7 humans later Frisk falls and it's like normal under tale, they cause Genocide routes when rare anomalies occur when chara possess frisk to kill everyone and attempt to take the rune from Sans.

Sans left the Au while it was on a genocide run and the Au collapsed, so it left no traces of. When in battle, he can transform the stone into gold full body armor, he also can summon a sharp bone as a hand held close combat weapon. His Gaster Blasters have solar crosses on their foreheads

Because of his insecurity of being rejected, he wears his cloak which covers his identity everywhere he goes;He helps Au's that are in trouble and is absolutely a good-hearted guy. He also loves the drink sarsaparilla (old-fashioned root beer). he likes to stargaze and is always friendly. His personality when with a friend is jokingly like and can be very sarcastic, he's also innocent and somewhat sheltered when it comes to life but don't underestimate his intelligence. He an all around fun-loving guy with a few cracks in his life.

The creator has told Gaster that his Au was made to hold on to the Rune, however the real reason why the creator gave Gaster the rune was because the creator felt bad that the Au was being scrapped (like Ink's Au) and decided it give it a purpose.

The run amplifies the beholders power and their fitting symbol appears on the stone. Rune = (his own personal symbol) solar cross= aka guardian symbol, Error= Corruption symbol = rune glitches out, Science Sans = Chess pawn= strategy, Chara= LV= black heart, Frisk = Love= heart, Ink = Paint Brush = creativity, Gaster= potion bottle= magic, etc. A person with pure intent can only touch the rune, like say, for example, a bad character like Cannon Nightmare tried to take it from Rune, when in contact, it would emit and electricity zap like shock that would hurt but not kill the pursuer.