Daughter

She was deeply shocked by the brutal death of her brother and is disturbed by her mother's behaviour of pretending that he is still alive. She is forced to live with her brother's corpse and watch him decompose as her mother plunges deeper and deeper into madness. Her real name is

Spoiler

Gloria

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In Ending 2 of Agatha's Agony, Gloria's parents overcome their delusions. They pick her up from the orphanage and live happily ever after.