Siblings VS. Changelings

Changelings, they rid you of your loved ones to change into them and use your love for them for power. But now that they have a new leader, they're even more dangerous than before.

A white pegasus with a brain Cutie Mark and a light blue unicorn with golden hair and a pentagram Cutie Mark, they both have the same mother, but different blood in their veins. Despite this, they still must work together to protect Canterlot from the new Changeling Invasion.