Impermanence

Rarity sends for Spike to be with her, in her final hours.

"Life is suffering." - Buddha

Decades after leaving Ponyville, Spike is consort to Dragon Lord Ember, and father to her children. Settled into his role as her diplomat, relations with Equestria have never been better. His life as a proper dragon is going well.
Until one day he receives a letter, a summons he can not refuse.