Asgore Dreemurr

Lord Asgore Dreemurr is the ruler of the Underground, and its denizens, monsters. He is the ex-husband of Toriel, the father of Asriel Dreemurr, and is the final boss of the neutral route.

Appearance
Asgore is a Boss Monster that resembles a large goat. He has an incredible shoulder span, a full yellow beard, and two horns. He appears to wear a suit of armor as well as a blue cape with yellow pauldrons. As shown by the size of his armor in-battle, he sports an intimidating stature. Among his many features, Asgore also dons a small crown atop his head.

Personality
He is depicted as a kind and loving family man; this is shown through his dialogue with Frisk during their encounter in the Pacifist Route, as he attempts to be as kind as possible despite this situation making him uncomfortable and shocked, going so far as to make small talk. However, from all that has happened to him prior to the events of Undertale, he is actually very depressed. During Undertale, he has several difficult decisions to make, which he disagrees with morally, but feels compelled to enact. This burdens him heavily. Asgore is also shown to be chivalrous, kneeling in front of the player after being defeated.

Main Story
Asgore and Toriel were originally married as King and Queen of the Underground, after being cast out from the Surface after the War. They eventually had a son, Asriel, as well as a second adopted child, the first human to ever fall through the Barrier. However, they eventually grew sick and died, all while Asriel was still young. Asriel ended up forming with the human's soul, and carried them past the Barrier back to their village. He sustained heavy attacks from the humans on the surface and ended up dying when he returned to the Underground.

This tragedy drew Asgore to the conclusion that all humans are dangerous, and decided to kill and harvest the soul of any human that falls through the barrier, so that he could gather the Seven Souls to become strong enough to destroy the barrier. Toriel was appalled by this grotesque decision, and forfeited her right as queen, divorced Asgore, and went to live in the Ruins, where she would care for any humans that fell through the barrier.

Between then and the start of the game, six additional humans fell through the barrier on Mount Ebott into the ruins, all of which Asgore eventually reaped the souls of.

Neutral Route
After travelling through New Home and arriving in the Throne Room, Asgore greets the player. He comforts them as he brings them to the barrier, where he gives the player a chance to turn back if they have anything left to do before the fight. Asgore does not mind the delay, admitting that he himself is not ready either.

When the player is ready to fight Asgore, he tells the player that it was nice to know them. He then draws his weapon and destroys the mercy button before starting the fight.

If you die to Asgore and then use the "Talk" action in the subsequent attempt, you'll get the following text: The dialog changes ("killed you twice, etc") until you get to five deaths, After five deaths the dialog will change to: After ten deaths the text becomes: It is not known if this means that Asgore has knowledge of the SAVE system. After being defeated, the player has the choice to spare or kill him. Either way, Flowey steals the six human souls that were revealed prior to the fight. The protagonist deals with Flowey, passes through the barrier, and escapes the underground alone. Asgore's death has a serious impact on the monsters.
 * "You tell ASGORE that he's killed you once before. He nods sadly. "
 * "You tell ASGORE that he's killed you five times. He nods grievously. "
 * "You tell ASGORE that he's killed you too many times to count. He nods pitifully. "
 * If he is spared, Asgore is surprised, but offers to take care of the protagonist since they will be unable to leave. Flowey appears and finishes Asgore off.
 * If the player kills Asgore, he dies smiling. Before the player can take his soul to be able to pass through the barrier, Flowey lands the final blow, shattering Asgore's soul. He notes how the protagonist has finally realized that this is a 'kill-or-be-killed' world.

Pacifist Route
When the throne room is reached, Asgore greets the Protagonist, and comforts them as he brings them to the barrier, where he gives them time to finish anything they still wish to do before fighting him. He then initiates combat with the player, but is interrupted by Toriel, who states how awful it is that he could seek to hurt an innocent creature such as the Protagonist. Then the other Bosses which the player has befriended arrive, and begin conversing, until Flowey appears, having stolen the six human souls, and begins to promptly steal the souls of the Bosses as well.

Flowey, fit with all of those souls, returns to his original form - Asriel Dreemurr. He then battles the player. After the battle is over, and the Protagonist is victorious, they convince Asriel to stop his plans, leading Asriel to destroy the Barrier and release the souls which he took into himself.

Asgore can be seen finally in the epilogue, asking the Protagonist if they would become the ambassador for monsters to humanity on the Surface. He is also shown trimming a hedge in front of Toriel's new school, implying they have reconciled to some degree.

Genocide Route
When the throne room is reached, Asgore makes a comment that implies that Flowey has spoken to him prior to the player's arrival; the player initiates combat and goes on to deplete his entire health bar with a single blow. Flowey returns to land the final hit as an attempt to appear loyal and useful to the player, however this fails and Flowey is promptly killed.

Toriel
His ex-wife, he wishes to befriend her, which she refuses. Before they separated, they used to be "insufferable together", as described by the Turtle Shopkeeper in Waterfall. They ultimately fell apart after the deaths of their children. In addition to general moral objections to war, Toriel became disgusted by his overall wishy-washiness in his decisionmaking; while he had the resources to solve the problem immediately, he instead chose to try not to kill anyone by waiting for humans to fall into the underground,secretly hoping no other human will come along so that no one will die,hence prolonging the suffering of the monsters in the underground.

Undyne
Undyne mentions to the player that when she was younger she met Asgore in person and challenged him to fights. After Asgore defeated Undyne several times, Asgore offered to train her, and praised her when she finally managed to knock him down during practice. Undyne mentions that she knows Asgore's favorite type of tea and that he often gets marshmallows stuck in his beard when he tries to drink hot cocoa, implying that he often comes to visit her home.

Trivia

 * Dreemurr, when rearranged, can be spelled as murderer.
 * In addition, when pronounced, "Dreemurr" sounds like "dreamer".
 * Asgore wields a red trident during his fight. Being a goat monster with a red trident, it is a possible reference to Satan.
 * Asgore, as seen in the scene before the battle with Asriel and the ending, seems to still have a complicated relationship with his ex-wife Toriel.
 * His favorite kind of tea is Golden Flower Tea, as stated by Undyne.
 * Asgore is also known as King Fluffybuns, a nickname given to him by Toriel. This nickname is also used by the Turtle Shopkeeper.
 * If you consume Toriel's pie in his boss fight, it reminds him of her and lowers his attack and defense.
 * Asgore has no flavor text when "Check" is used during battle.
 * During the first-run Pacifist / Neutral route Asgore Boss battle, his sprite appears to be arranged in such a way that it appears to be either Asgore looking down in shame, or an eager maniacal grin, depending on how it's viewed.
 * By analysis of the multiple crumpled up pie recipes found in New Home, it can be assumed that after Toriel left him, Asgore attempted to recreate the way her pies tasted - though he could never truly replicate it.
 * The name of the song that plays just prior to Asgore destroying the Mercy option, "Bergentrückung", is a German word referring to a mythological motif in which a heroic figure dies and their soul moves on to rest within a mountain (or other location), leading to what can be referred to in English as "king under the mountain". Combining the two song titles that play during the fight, they could be read as "king under the mountain, ASGORE."
 * Since there is a flavor text that mentions a Santa costume, one can assume that Asgore is the Santa of monster world that leaves the presents under the tree in Snowdin.
 * Asgore is immortal, since Boss Monsters only age when their children do, and according to Gerson, he will most likely stay stuck at the same age forever.
 * If you type "Asgore" for the character's name, the response becomes "You cannot." and prevents you from using the name.