Because her soul is enslaved to a goddess; Oniisama E

By all means, Oniisama E, translating as Dear Brother, is unassuming in its premise. However, pegging Oniisama E as anything other than a landmark production would be short-sighted. Ikeda Rioyko’s original manga was penned in the 1970s, and yet the series moves through triggering subjects like terminal illness, suicide, incest, homosexuality, and drug use without batting an eyelid.