"Voyons, laissez-nous voir" Akio spoke, in some rather nice French. "Châtiment....ah, I'm sorry. You don't speak French, do you?"
Akio just gave a wry smile as he came over, while Ven was being held down and was unable to move. "Listen, its unfortunate for you that you happened to be the first person to break into my room. You see, I do have to set an example after all. Now...if it makes you feel better, I won't be cutting you open today!"
This was the first time someone entered his room without invitation, or it being an emergency...well, sometimes some of the maids did to wake him up, but they had received permission to do so. Therefore, Akio had to set an example. That said, he didn't want to risk killing the guy right off the bat either, thought that might be bad for him.
And so, Akio took out a book, drew some blood from Ven, and put it in the book, before placing it back on a nearby table. That was actually a book that let him summon duplicates of whatever he put the blood from into that. It was also Soul-Linked to Akio so only he could use it.
And then, he took out another book and a staff. "I have decided what I am going to do to you. Now, you might have some unpleasant experiences after I test this spell out on you. It has been untested so far, because I need a target for the effect, and of course its hard to get volunteers to test it out on. So thank you for 'Volunteering' for this. Now...."
And then, Akio chanted the spell. "Glaoim ar na biotáillí neamhghnácha, cónaí taobh istigh den duine seo, déan an t-árthach atá i bhfolach air agus gníomhóidh sé leis na mortals, agus lig sé le réimse an duine leis an gcosc seo." (I call upon the unholy spirits, dwell within this one, make him the hidden vessel that will act with the mortals, and let him traverse the realm of man with this cloak of concealment!)
Once the spell did take hold, what would happen is that the target would first feel intense pain and agony, enough that his screams might be heard from anyone in the area. At the same time, his body would appear to change slowly...indeed, although he would still smell of vampire, the magic took away the paleness of the skin, performed some other maintenance, and while it was all very painful, if one was the type of vampire who no longer had a heartbeat like most, they would feel the unpleasant, agonizing experience of their heart beating inside their own chest.
And yet, the vampire fangs were still there, as well as all the abilities. That is the effect shown by anyone who would be hit by this spell. Although any vampire or experienced individual would easily see through it on close inspection, from a distance it would be able to fool even the eldest of vampires.
In other words, the spell was a concealment spell to let vampires have a better chance of hiding among mortals.