Sombra, the dreaded King of Darkness, was defeated and his body shattered, but his dark soul survived the return of the Crystal Empire and went into hiding. Some time later it found a path between worlds, a mirror portal, and arrived in a place called Hueco Mundo, where it gained a new body to start a new life. In the process Sombra loses his memories and becomes a shell of his former self, searching for something that he knows that he lost while having no idea where to find what he was missing.

Along the way he somehow finds his way to Karakura Town, into the hands of Kisuke Urahara, and learns more about his new body than he could have learned on his own, before coming into contact with Ichigo Kurosaki and his small group of friends. From there he starts an epic journey to help them save another friend from a terrible fate, fight the people that were in their way, and face an evil that was hiding in plain sight at the same time... along with finding out what happened to his missing memories.

(Bleach/ MLP Crossover)
(Part of the Universe 13 story series, though reading the other stories is not required)
(Also, the story will not include the Fullbring or the Thousand Year War Arcs)

He was an alien raised by humans, torn between two worlds and belonging to neither. His efforts thwarted, he found himself descending into madness, destined to be consumed by the nightmare he was becoming.

She was a loner, withdrawn and anti-social. When one whose regard she valued above all others turned away, she sank into darkness and despair. The madness waited.

The madness drove him to decide that if the world could not accept his enlightenment, it would suffer his madness.

The madness drove her to decide that if the world had no place for her, then it could do without her.

Sometimes, it takes another broken soul to help put your pieces back together.

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Part of the PWNY-verse.

Edit: Cover art by Sanyo21, commissioned by Level Dasher
Edit 2: Since everyone keeps asking, this is a crossover with the 'Mother' game series. Look it up.

Jak never found it unusual that he had a unicorn brother. Shining Armor had been there his entire life, as far as he could remember. Sure, Daxter often made a point of just how strange it was relative to everyone else in the village, but then again Jak himself was different from the rest of the villagers.

He never questioned that he looked somewhat different from everyone else. Never questioned that he was raised by Samos the Sage, alongside Samos' daughter Keira, whom he kinda-sorta liked and who kinda-sorta liked him, even if Samos himself didn't like that. Jak, by nature, wasn't the sort to question things.

Shining Armor, on the other hand - or hoof - had lots of questions, but no answers.

...yet.

Part of the PWNY-verse.

Crossover idea suggested by Keyblade Hero.
Cover art by Sanyo21

Chrysalis has heard rumors of a crystal mirror having the power to take ponies to other worlds, where they gain powers that put them on par with the likes of Princess Celestia or even the Spirit of Disharmony himself. She wishes to use the mirror for her own ends, so she can gain the power to finally have her revenge on the ponies that have taken everything from her and maybe regain her empire in the process. The world she finds, however, is the dark interior of a ship that is being overrun by dead creatures that will stop at nothing to kill her and the repair crew that came to fix the ship.

She must quickly get used to her new body while fighting the hordes of the dead, come to terms with all of the horrible decisions she has made over the years, and maybe see the light that the ponies talk about... provided that she, and her new companions, don't get killed first.

(Dead Space/ MLP Crossover)
(Part of the Universe 13 story series, though reading the other stories is not required)