Undertale

Undertale is a roleplaying video game develooped and published by tobyfox.

Plot
Long ago, monsters and humans ruled the Earth together in peace. One day, war broke out, and after a hard and long-fought battle, the monsters were banished to the underground, a massive cave large enough to have its own weather system. They were sealed in by a magic barrier, created by the human's seven greatest magicians. Anyone and enter through the barrier, but only something with an incredibly powerful soul could make it out. You play as the human Frisk, who has fallen through the barrier, and strives to make their way out. You can make many friends, or you can kill them all. But be warned-if you kill to much, you may lose something that is impossible to get back. ..

Fandom
Undertale is a very popular game due to its unique design and great story. Some people do not like it because it is "old school," but many fans believe that it is very unique, and almost nothing like an "old school" style rpg.

Het

 * Soriel - Sans and Toriel
 * Asgoriel - Asgore and Toriel
 * Undyrus - Undyne and Papyrus
 * Muffeton - Mettaton and Muffet
 * Muffgore - Asgore and Muffet
 * Alphgore - Alphys and Asgore
 * Dogi - Dogamy and Dogaressa
 * Mettataton - Mettaton and ???

Slash

 * BurgerCream/NicePants - Burgerpants and Nice Cream Guy
 * MettaSans - Mettaton and Sans
 * Papyton- Papyrus and Mettaton
 * Grillbyton/Mettaby - Grillby and Mettaton
 * Sansby - Grillby and Sans
 * Fontcest - Sans and Papyrus

Femslash

 * Alphyne - Alphys and Undyne
 * Cratty - Bratty and Catty

Non-binary

 * Charisk - Chara and Frisk
 * Asrisk - Asriel and Frisk
 * Chasriel - Chara and Asriel
 * Papyrisk - Papyrus and Frisk
 * Frans - Frisk and Sans