A is a young Sith and an apprentice to one of the Sith Lords that make up the Dark Council. Among his master's apprentices, he is favored due to his strength in the Force and believed to have the potential to follow his master into becoming a Sith Lord. Due to his power, A has become his master's hand, his chief enforcer, and granted certain freedoms and luxuries beyond those of his fellow apprentices, one of which is B. B was a gift to A from his master, a slave meant not only to serve A but also act as proof that A was capable of controlling others. B could have been born into slavery, captured during the war or was forced into slavery due to disgrace. Despite A's reluctance at accepting the slave, B proves himself to be useful and becomes A's confidant. Together they must do as their Sith Master commands while protecting themselves from the ambitions of A's fellow apprentices and hiding the feelings that are developing between them.
Alternatively, same line as above but set in an Urban Magic setting. A would be the apprentice to a powerful sorcerer and B is his slave/guardian (human, demon, lycanthrope, etc.). I'd be open to playing in an AU world where magic is known to the public and the world is broken up into different fractions (humans ruling certain republics/kingdoms, magical groups ruling others, war happening between them).
((I'd prefer to play A but I'm open to playing B as well.))
The world is dying. Wars and disease kill the men. Disasters scar the earth. Magic flows so thinly that only a handful of people are left that can feel and manipulate it. Not since the Dark Years before the coming of the King has the world suffered so and it will only get worse. In the early twentieth century the Eight Lights were once again born into this world, tasked with uniting their incredible powers to rejuvenate the world and return balance once again. For the first time, the Lights vanished before completing the rejuvenating process, failing their mission. Now, more than a half-century after the last Light vanished, A has been marked by fate as the world's last hope when he accidentally frees B, one of the lost Lights, from the magical prison that had been holding him. Together the two must race not only time but also a cult seeking to harness the power of the Lights for their own use.
((I'd prefer to play B but I'm open to playing A as well.))