|“||Human...It was nice to meet you. Goodbye.||„|
|~ Asgore before fighting the player.|
Asgore Dreemurr is a major antagonist in the 2015 indie game Undertale. Although he is built up through the entire game as the main antagonist, when confronted he reveals himself to be a kind and cheerful yet sorrowful and regretful king who feels that he can no longer betray his promise to his people. In the end, the true main antagonist is revealed to be Flowey. Asgore also appears as a minor character in the first chapter of the 2018 spin-off game, Deltarune.
Unlike the apparent person of Flowey, Asgore is an anti-villain, though while he is plagued with guilt and regret, he's still the main obstacle, sending myriad troops to kill the protagonist Frisk, and in the end fighting them himself.
Asgore has been described as both as a pushover and soft by Papyrus and Undyne respectively. He is very friendly to everyone he meets, cares deeply for his subjects and loves gardening. He is not a killer at heart, during the fight with Asgore, he apologizes for having to kill Frisk and does not look Frisk in the eye during the fight, he is unwilling to fully go through with his plan, wanting to stay in the underground under the faint hope that 7 more humans will not fall there and that his plan won't come to fruition.
Before the events of the game, Asgore was king of the monsters since before they were driven underground. After being driven underground, the monsters were nearly driven into despair at their predicament. Eventually, his son Asriel found Chara who had fallen into the underground which restored hope to the monsters. After the death of Chara and Asriel, he swore in a fit of anger that any human that fell into the underground would be killed and once he had collected 7 human souls, he would use those souls to become a god and wipe out humanity. His wife, Toriel became disgusted by his declaration and left him, Asgore himself being unable to rescind his declaration due to it restoring hope to the underground which almost fell into despair again with the deaths of Asriel and Chara. At some point between his declaration of war and the events of the game he encountered Flowey in his garden, took care of him for some time before Flowey left on his own.
In the neutral route, he serves as the penultimate boss (final boss if Flowey had already been defeated in a previous run). When Frisk encounters him, he greets Frisk and states that he would offer Frisk a cup of tea if they wouldn't have to try to kill each other soon. He tries to comfort Frisk at what is about to happen soon and even allows Frisk to leave and undergo any unfinished business before they fight. During the fight itself, he states that he is glad to have met Frisk before breaking the mercy button so that the player cannot spare him. At the end of the fight, the player can choose to finish him off or spare him. If the player chooses to spare him then he says that he will end his declaration of war, try to reconcile with Toriel and take care of Frisk as a family. If Flowey has not been fought before then Flowey kills him. If Flowey has been fought before then Asgore realizes that all of that is impossible. He requests that Frisk take his soul, go to the surface and try to find a way to free the monsters before committing suicide.
In a pacifist route, before they can start fighting, Toriel stops him with a fireball. At first overjoyed to see Toriel, he is rebuked by her when she states that he could've gotten 6 more souls from the humans after the first but was too cowardly to carry out his plan. During the reunion with everyone, he gets grabbed by Flowey. After protecting Frisk from Flowey he gets absorbed by Flowey who becomes Asriel. During the fight, the player has to save him after his memory is wiped. After restoring his memories, Asgore declares that "You are our future". After the fight with Asriel, the whole group leaves the underground. In the credits, Asgore can be seen trimming a hedge into Papyrus' head in front of Toriel's new school. It is implied in the credits that Asgore does manage to reconcile with Toriel.
Like in the other routes, Asgore is met in the throne room, having been warned by Flowey. He tries to talk down the player but gets killed by a sneak attack from Flowey.
Asgore takes on a more peaceful role here, not being the king of monsters but instead having a flower shop on the surface.