Esther is a new unit introduced in Metal Slug Attack.
A young woman from a minority people living in an underworld in which a different ecosystem from the Earth's one was formed. Since this peace loving girl became her clan's representative, conflicts have decreased and negotiations for a co-existence pact have been moving forward bit by bit.
She has special abilities allowing her to understand space, even in the darkness thanks to a little light emitted by living beings, and she also possesses special equipment on her face which boosts this ability. The caterpillar that's always with her is her friend and was born on the same day.