Mercia Koster

 was one of the original residents of Vault 87, who died during the FEV experiments conducted in the Vault. She was one of only six residents in the vault to die from something other than the experiments themselves. According to the Vault 87 terminal entries, she died of natural causes due to cancer type 1 categories.

Appearances
is only mentioned in Fallout 3 in one of the Vault 87 terminal entries.