And as for a new character. Something experimental..
How about something sent by or escaped from the organisation?

tl;dr The organisation edition.

As far as is known on the organisation in the game by few player characters:
The organisation is heavily inspired by the SCP foundation. We've discussed and agreed on that not everything on that website is automatically cannon in this setting, things must be introduced OOC and agreed to. Some SCP's would not go well in this setting.
Martin worked for the organisation, that's where he got the stone and where he makes his calls to.
The organisation has extensive records on supernatural activity and a large network of agents and locations.
The organisation strives for the development of mankind. They wish to protect it from extinction, but they also understand that 90% of both humankind and vampirekind has to go. Thus they supported the war on both sides.

Of course, not every player has the same info and some of it may be wrong. Even Martin doesn't know everything, just the info he's classified for.