One of the most popular characters; a skeleton
What is Sans
The only canon ship in the original Undertale game
What is Alphys X Undyne?
The AU where Sans kills everyone he loves in order to defeat the genocidal player
What is DustTale
The royal scientist
What is Alphys
Not a canon ship, but is adorable nonetheless. One of the characters (a skeleton) idolizes the other character (Who is VERY fabulous) throughout the Undertale game.
What is Papyrus x Mettaton
The AU where the characters have swapped personalities
What is UnderSwap
The main character, who is controlled by the player
What is Frisk
This is a fairly popular ship in the fandom. One of the characters is a skeleton, who is a fan favorite. The other is a fiery bartender. Both live in Snowdin.
What is Sans x Grillby
The AU where Frisk, Flowey, and a part of an Amalgamate fuse together and turn into a dog to save W.D. Gaster
What is Dogs of Future Past
The head of the Royal Guard
Undyne
These two were married in the past, with a biological son and an adopted human child, but are currently on rocky ground.
What is Asgore x Toriel
The AU which explains Sans and Papyrus's origin. In the AU, Gaster (Their creator) does cruel experiments on them, and plans to use them to break the Barrier.
What is Handplates?
The man who speaks in hands
W.D. Gaster
These two characters show up during the game. Both sell things to the player, though one of them is very unhappy with his job and his boss, Mettaton.
What is Nice Cream Guy x Burgerpants
The AU where the Riverperson tries to warn Frisk of Gasters presence, but Frisk ends up getting kidnapped. Sans is forced to team up with the watery stranger in order to save them.
What is The River's Warning