MLP/Undertale crossover.
Not a PWNY-verse story.

Long ago, the Monsters and Humans fought a great war. The Monsters lost, and were sealed in the Underground. It would take the power of seven human souls to break the barrier that kept them imprisoned. They only had six. And so the Monsters waited and hoped, praying that another human would find their way to the Underground. Some thought the seventh soul would give their King the strength to break the barrier. Some dreamed of a human who would be their friend, and save them all...or had nightmares of one who would bring back the war.

...but nobody came.

...but somepony did.

Eons after the war, with no way to tell how much time had passed above, a tiny blue filly with wings and horn fell into the underground, calling for her Mama. None knew the poor creature's nature or origins...but her soul was powerful with magic, even more so than a human soul.

None can know what will come...of this little 'Woona'.

Cover art by Sanyo21

This story is a sequel to Memoirs of a Royal Guard

From the outside looking in, life has never been better for Silent Knight. He is the first pony in a long line of Royal Guard ancestry to earn a commission, he has a loving mare by his side, and he bears the kingdom’s highest honor for bravely risking it all to protect Princess Luna. The future shines bright with potential, but the shadows of the past lurk at every twist and turn that lies ahead.

Guilt, anger, and regret are constantly at war in the depths of Silent Knight’s mind. Despite his best efforts to enjoy the life he has, he finds himself trapped in the past, reliving the moment when his unit was ambushed and his ponies were killed. He refuses to show any weakness, instead hiding everything behind a tough face to protect himself and those he loves. But his true feelings—and what he plans to do with them—shackle everything he holds dear with chains forged in secret.

Secrets of a Royal Guard is a comedy series with romantic, dramatic, and adventure elements. It features an original character cast and their interactions with the princesses they protect. It is recommended that readers be familiar with Memoirs of a Royal Guard.

Quill & Blade Universe

This story is a sequel to The Dragon Sage

After the events that took place in The Dragon Sage, Twilight and Spike have quietly started living and loving in their castle. Other ponies are bound to find out, so how will they respond? What does this mean for their friends and neighbors?

If you haven't read the previous story, I suggest it, but it is not necessary. Most characters and references to The Dragon Sage take a back seat role in this slice-of-life story. It's more as an extended epilogue than anything else.

Spike's happy world has always revolved around Twilight. From his hatching to their adventures in Ponyville, he has remained a faithful companion and loyal friend. But why is it that he has remained a baby for all of these years? There is so much about dragons that they do not know. In a rude awakening, Spike receives a letter from Princess Luna who promises to help Spike meet his potential. But how much will he change? Will his friends see him differently? And how will his life with Twilight evolve?

(set after season 4 and rainbow rocks).

In a remote corner of the Solana Galaxy lies a backwater planet called Veldin. Nothing important ever happens there. Nothing exciting, either. Ratchet, a Lombax with no idea of his origins, is beginning to grow bored with his life, and dreams of excitement. He wishes on a falling star for some excitement to find its way into his life.

The falling star answers by crashing into his home in the form of a basket carrying a tiny creature with a horn, a pair of wings, and four hooves. The name on the basket reads "Twilight Sparkle".
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Part of the PWNY-verse.

Edit: Now with cover art by the amazing G_Haze
Video Consultant/Technician: m2pt5 (he provides the infobot videos and similar.)

Edit: Game Timeline
Ratchet and Clank: Done
Going Commando: Done
Up Your Arsenal: Done
Deadlocked: Done.
Size Matters: Done.
Tools of Destruction: Done.
Quest for Booty: Done.
Crack in Time: Done.
All 4 One: Done.
Into the Nexus: Done.