Cataclysmic Bliss
Premise
In the year 0 of the Final Calendar, an alien race known as the Despair attacked humanity and destroyed the homeland through the power of massive humanoid psychic weapons that caused mass suicides simply by their presences and overwhelmed any with the mental fortitude to resist with incredible power. Society collapsed overnight, and those who somehow avoided the worst of the disaster were forced beneath the land where the psychic powers of the aliens could not reach them. There, for decades humanity struggled painfully and eeked a pitiful existence beneath the crumbling ruins of the old world until the aliens' weakness was discovered.
Harnessing the very same psychic technology as the Despair used, humanity mounted a counter-offensive using the power of joy. Those first generation pilots, often called bliss drivers in reference to where their power is obtained from, were a particular sort, with twisted emotions that allowed them to revel in battle and grow stronger by fighting. Their growth was unparalleled, overwhelming even the alien menace and coming to dominate them with powers hitherto unseen. The war-ecstatics (and later Deviants), as they became to be known were eventually rejected by humanity as their passions led them to become too twisted and exiled into space by the massed armies of newer (but inevitably weaker) bliss drivers.
Humanity has rebuilt a new society on the ruins of the old, a saccharine, nonviolent society of mandated happiness where the power of human joy has granted humanity power over the cosmos, the elements of nature and even their own evolution. Spread out across the stars, stronger than ever- and yet the knowledge that something greater still is out there looms.
That fear has eaten away at the joy of humanity. You, bliss driver have enjoyed a privileged lifestyle where your ever whim and need was catered to, your life structured to provide challenge and hardship to make your experiences more real and intense than those of an ordinary person. In many cases, your neurochemistry itself has been adjusted to experience greater peaks- at the cost of deeper lows. You have heard of the Deviants and the victory they brought to humanity at cost to themselves, and have spent your life training for a war you hoped to never fight.
Now it is the year 1000 of the Final Calendar, the Deviants have returned.