(The story before this is not necessary to understand this one.)

Opaline's will to live is slowly waning. Her power is gone and it doesn't look like she'll be able to get it back anytime soon. Only her blistering rage against Twilight is keeping her here on this earth. That is, until she finds a unicorn filly without parents.

Part of my headcanon, so yeah, if you disagree, then you disagree.