He was Born as the Sans of Vialtale, a technologically advanced yet oppressive world and Underground, Azure had led a comparatively similar life to most Sans variants, being the brother of Papyrus Serif and a Royal Scientist. Eventually, he would encounter his world’s Frisk and help her to convince Asgore of stopping his crusade against Humanity and later defeat W.D. Gaster from destroying all of Humanity. However, this happy ending would soon be taken away by a variant of Insanity Sans that invaded his AU, killing everyone he knew with only him left as the sole survivor due to the falling in the Orrery. But one day..he returned, and wants revenge and is coming for Insanity Sans

Azure: "Even if everything is set against me, I will never submit. I will stand my ground until I bring justice to the SOULs of those that passed away that day and execute their killer. Even if this is the end of me, I will keep walking until every last one of them has been avenged."