Now here's something I've been toying with for a while but can't seem to write. I'm just going to throw it out there so that someone else can see it and write it if their interested.
Harry is a wandering sorcerer and Master of Death that has lived for many millennia (because death is an asshole that refuses to allow his "Young Master" to die) traveling the many universes and worlds.
Death is an asshole that is a closet tsundere, yandere, and a dundere all rolled into one and is completely focused on Harry.
Harry is sent into the ViewFinder universe by Death while he was in the middle of battle in another universe in his animagus form (some sort of big wild cat, or wolf or direwolf) into an alleyway not too far from where Takaba Akihito lives. He is injured and passes out from blood loss in the alleyway in his form.
Akihito had been running from another criminal that he had pissed off and had ducked into the alleyway to hide (this is before he meets Asami), and finds Harry in his animagus form and, because his heart is just too big and he is just too compassionate, he takes Harry home to care for him.
Harry wakes up in his animagus form to find that a non-magical human had taken him home and healed him, and finds himself staying for a while. Akihito tries to find a home for Harry (who he renames), but finds that all of the posters that he puts up are missing the next day (Harry). Harry eventual reveals his human (original) form to Akihito when he protects him from (another) criminal that Akihito had pissed off, and Akihito is complete ok with it. They start a slow relationship.
Fast forward to the beginning of the ViewFinder Series, and Harry has taken to shadowing Akihito as a bodyguard in both of his forms (depends on the job and how he is feeling that day). The day Asami corners Akihito, Harry is with him in his human form and when they jump off the roof together, they disappear with a loud 'CRACK!' (apparition) and Akihito doesn't break his finger.
Harry, because of the different situations his dimensional traveling had placed him in, had researched and studied the underground and black market of this world, so he does know who had tried to corner them and warns Akihito. Meanwhile, Asami is gathering information on both of them and finds them intriguing, especially Harry, who is a ghost in the legal and illegal system.
At the docks, while Akihito had been captured like in the canon, Asami had to fight Harry into submission, who had gone to scout and the man who grabbed Akihito had only gotten lucky with his timing. Asami had to use a needle with a knockout drug in it to knock him out, and it had taken several of them to do so.
When Harry wakes up, it is after Asami had already started on Akihito since Harry had been knocked out with a much stronger drug that should have had him under for another two to three hours, but it's Harry and we don't question it. Harry gets angry and breaks the restraints that were holding him and throws Asami away from Akihito, all the while shifting into a hybrid form of his human and animagus forms, shocking Asami.
Harry basicly destroys the bonds on Akihito and grabs their things and clothes them faster than the eye could see, all the while keeping Asami in his line of sight and growling at him if he moves. When Asami tries to stand up and rush Harry, he finds that Harry was not going to play nice as Harry digs his claws into the man's chest and back in retaliation and anger, causing Asami enough pain and enough of a distraction for Harry to escape with Akihito riding on his back in his full animagus form.
Harry spends the rest of the night getting the drug out of Akihito's body and reaffirming his place as the boy's mate, with Akihito's permission of course. Harry places Akihito under some wards that only allow Harry to enter and leave, again with Akihito's (reluctant but fond) permission.
During this time, Asami finds and corners Harry again while Harry was returning from the grocer. Asami tries to capture Harry, but ends up fighting him again and finding out that Harry is not only a 'shifter' but also an 'elemental' as Harry uses water and wind spells and magical manipulation to divert any and all bullets, needles, and darts from himself. Harry escapes, but Asami is more intrigued with the duo than ever before.