This will basically follow Fate/Stay Night fame and characters but will take place in a different time point. 3 new characters are present in this story as well as most of the canon characters from the Visual Novel.
The plot centers mostly around Ryugo Tsudamaki who accidentally summons the servant known as, Zoah-Daimoah. Because he can not fully control Zoah's actions Ryugo seeks help from the skilled Magi; Tohsaka Rin to aid him in keeping the elephantine servant in check. However, as he's studying, something strange begins to happen...
What you can NOT do
-The only thing that you can't really do is kill off the main characters provided, while I am aware that some deaths can be nessacary in order to make a story more interesting I just don't see it happening now.
Mature Content and Rating
-If you've played any Type Moon Visual Novels then you'll know that there are infact sex scenes in the visual novels. That being said you can plug them in here as you see fit so long as you can handle it, of course.
Chapter Length
-If you're going to add on to this then I won't ask much of you but please put some effort into it. One-liners or sentances are just plain lazy. So basically either you put some thought into it or don't do anything at all, simple as that.
Non-Canon Characters
Ryugo Tsudamaki: An ill-fated sophmore who is currently studing to become a private investigator in a university at Fuyuki City. Level-headed, but easily startled, Ryugo sticks close to reason and rationality. Although her has no knowledge of Servants or Masters he is a latent Magi due to him being the reincarnation of his grandfather (whom was a great Magi). He is currently studying magic to help maintain his servant Zoah-Daimoah.
Zoah-Daimoah: A Berserker Class Servant who just so happens to be the reincarnation of an Indian God in the shape of an giant bipedal elephant. Zoah can be arrogant being he feels it's his duty to enforce the 'None Shall Pass' law (even though said law doesn't exist). What really makes Zoah dangerous is his impulse to go on rampages when he's the slightest bit angry, this action usually results in a massive amount of damage which is why Ryugo is trying so hard to control him.
-If you need to know the canon characters of Fate/Stay Night go to the link below
http://en.wikipedia.org/wiki/List_of_Fate/stay_night_characters
or ask me personally if you don't trust wikipedia.
With all that out the way, feel free to add on to what parts you want.