Undertale: Twin sister

After Frisk goes missing, Caitlin, Frisk's twin sister goes looking for her in the the last place she saw her. MT Ebott, the mountain of dark legends, she finds a necklace that belonged to Frisk on the ground. Just like Frisk, Caitlin tripped and fell into the Underground. Caitlin finds things she never knew existed.

Aphmau's UnderTale Life

lately Aphmau has been sneaking off, she doesn't come back until really early in the morning, her friends begin to worry so they follow her but will they understand her life in UNDERTALE?