((This is something I've been working on with
Kolyat, so partial credit goes to him.))
The Assassin and Templar orders both share the same goal: world peace. How they wish to achieve this is where they disagree, as you should know. The leaders of the two groups are the radicals, the extremists, but what of the common followers? They strongly agree with the principles of their respective order, but usually dare not go to such heights. One cannot doubt their sincerity, though. Our role-play will revolve around the lives of two low-level, simple citizens of Italy, Constantinople, Damascus, or which ever location you so desire.
The Assassin, to prove his/her worth, is sent on his/her first mission: to quiet a certain Templar forever. Said Templar is just like him/her, a typical commoner. He/She teaches philosophy and is horrendously outspoken of his/her views on society. He/She has gained a small following among his/her students, and that is something the Assassins definitely do not need. The Templar, however, should not be killed outright, the Assassin higher-up said. He/She is suspected to have knowledge on the Templar plans, and possibly on the whereabouts of a Piece of Eden. The elder orders the Assassin to develop a long-term relationship with the Templar, draw out the information, then dispose of him/her.
The Assassin accepts, approaches the Templar as a student, then gains a foothold into his/her life. A student notices his professor's favoritism for the disguised Assassin, and is infuriated by jealousy. He calls out the professor to his/her peers and students. The Templar Order hears word of this, but takes little heed.
The two's bond grows, whether romantically or not is your choice. The Templar has been spending too much time with the Assassin, and the Templar Order becomes increasingly suspicious. The Assassin Order sees this, and demands that the Assassin end the Templar immediately.
The Assassin and Templar are alone one night, somewhere, but the Assassin hesitates. He/she has spent a lot of time with the Templar, understanding his/her reasons on becoming a Templar, and his/her sincerity to his/her cause. The Assassin reveals himself/herself, and the Templar is startled, but soon regains his/her composure. Of course, it was not that hard for him/her to accept it, knowing the Assassin's standing.
The Assassin leaves the Templar alive, then returns to his/her order, probably with a falsified piece of proof of the Templar's death. Later, somehow, the Templar regains his trust the Templars, and rises through their ranks. He eventually is allowed to see a Piece of Eden, or is given the location of one, entrusted to care for it. The Assassin and Templar meet once again in secret, then decide to take the Piece and hide it, hide it away from the extremists of their orders, hide it from the greedy grips of humanity. They travel to a faraway place to ensure its secrecy, but they could meet trouble along the way.