TrioTale

TrioTale is an AU where Ralsei, the goat prince from Deltarune, is the firstborn child of Asgore and Toriel, with Asriel being the secondborn. Chara remains the first fallen human and is found by Asriel. Both Ralsei and Asriel view Chara as a sibling and the trio get into more trouble than they should.

Character Changes

 * Since Ralsei is the firstborn of Asgore and Toriel, he is next in line for the throne.
 * Chara is considered royalty alongside their adopted siblings but doesn't care for their title.
 * Chara never consumes the buttercups and is generally happy, although they're still a strange, disturbed child that can always be found clinging to Asriel or lingering nearby.
 * For the most part, the characters' personalities do not change.
 * Frisk is the second human to fall several years after Chara arrives. While the monsters in the underground have grown to love Chara, the appearance of a second human makes many monsters uncomfortable.
 * Since Chara never died, Asgore never sets out to collect the souls of any future humans that fall.
 * Flowey also does not exist due to Asriel never dying. Toriel and Asgore never separate.
 * The royal guard is led by Undyne and Papyrus.
 * The royal guard is still tasked with capturing any future humans that fall but will not fight them unprovoked.
 * Despite the laws that Toriel set into place for any fallen humans to be spared, some monsters ignore the Queen's law and try to attack Frisk.
 * Since Toriel and Asgore never separated, Toriel does not live in the ruins and instead resides in the castle with her family.
 * The royal kids check the ruins for more fallen humans occasionally.

Gallery
Ralsei's canon design for Triotale

Trivia

 * Ralsei's fur was originally going to be black. This idea was changed last minute.
 * Chara was going to be a female. Their gender is left up for the reader to decide.