Before he was Flowey, he was Asriel, King Asgore and Toriel's son. After his adoptive brother/sister Chara died of illness, Asriel used Chara's soul to cross the barrier. He became the Hyper Angel of Life. He gave Chara's wish to die peacefully in a bed of golden flowers. Unfortunately, the humans thought he killed Chara. Asriel refused to fight and showed mercy, which the humans didn't accept. So Asriel got brutally beat and burned. While barely alive, he made it back to the Underground where he died. But his dust blew onto a golden flower. He became a living flower. Afraid of what his parents might think, he ran away.
The king was so devastated that he became evil. He held an even stronger grudge against humanity and declared war. Toriel left Asgore and a new rule has been declared. That rule is "Kill or be Killed".
Flowey, like his Undertale counterpart, still believes in the "Kill or be Killed" motto but is more on the "Be Killed" side. However, after meeting Frisk, he started to believe in a new motto, "Save or be Saved".
Flowey is shown to look the same as his counterpart, however, the petals are shown to be torn, similar to how Flowey appears at the end of the Omega Flowey fight in the Undertale universe. His eyes are black. His face is peach and his petals are yellow.
Flowey is shown to be similar to Undertale Asriel - usually happy, but can also get upset and cry a lot. He is afraid of the monster of the Underground and terrified of the king, despite him being his father.
Powers and Abilities
Flowey has the same powers as his Undertale counterpart. He can manipulate seeds which can hurt and damage the opponent. Only, he refuses to hurt anyone. He can also change faces. Only instead of using them to show an evil personality, he uses them to scare off enemies and monsters to show that he is tough. This mostly works.
The fight against Flowey takes place in the Genocide run. Flowey realizes that you've become an even worse monster than the monsters underground, and decides to try to stop you.
Alpha Flowey - The fight against Flowey takes place in the Genocide run. Flowey realizes that you've become an even worse monster than the monsters underground, and decides to try to stop you.
Asriel Dreemurr, the Hyper Angel of Life - After losing to you as Alpha Flowey, Flowey is about to give up, but realizes that if he gives up now, humanity and the rest of the monsters WILL perish. Knowing that the fate of the whole world is on his "shoulders" now, Flowey generates enough determination to transform to "Asriel Dreemuur, the Hyper Angel of Life".
Frisk - Flowey accompanies Frisk on yours and her journey to escape the Underground, as well as avoiding monsters together. Flowey protects Frisk from the dangers of the Underground even though he is terrified of the monsters that are around of the Underground. Flowey even thinks of Frisk as Chara sometimes.
Sans - Sans dislikes Flowey and Flowey dislikes Sans.
Toriel - Flowey knows about Toriel and her insanity and even tries to warn Frisk about her. He is afraid of her, even though it's his mother.
Asgore - Flowey is terrified of his own father.
Chara - Before Flowey became a flower, he was Asriel Dreemurr. He saved Chara and this is where the Dreemurrs adopted them. Chara was very close like in Undertale. She and Asriel shared a much stronger relationship than in Undertale because Chara didn't want to destroy humanity but get away from it. So Asriel saw Chara as special and even sometimes accidentally calls "Frisk" Chara.
This article is taken from Underfell Wikia Credits to the original Authors