I'm thinking of apping a Wraith from Stargate Atlantis. Since most of his actions would be based on his hunger for human life force, how would feeding work out? How long would he have before people aboard the station notice one or two nameless NPCs disappearing every month or so?

Furthermore, would he be able to grow new organic tech in the event that he needs/loses something? The amount of power needed to pull it off is considerable, so I wouldn't expect him to do it without consequence - I'm just curious if it's possible or not.