When the Elements of Harmony unite with their true bearers; the first seal will be broken.

When the guardian of Tartarus abandons his duty; the second seal will be broken.

When the dark king dies and the heart of crystal stands restored; the third seal will be broken.

When the spirit of chaos submits to harmony; the fourth seal will be broken

When the vessel of harmony reaches her full potential; the fifth seal will be broken.

When first corrupted pony dies where it began; the final seal will be broken.

and true harmony shall finally dawn on Equestria.