Dante is a half-demon, demon hunter. This means his senses are pretty damn sharp, such as eye sight, hearing, and sense of smell. He also inherited a nifty little skill from daddy Sparda that lets him sense when demons or beings with demon blood are around. Hell, it lets him know where they are in relative position to himself.
Given how many other supernatural/non human beings we have on board the ship, I thought it would be apt to expand Dante's abilities, within limits. Let me know which ones apply to your characters!
1) He can sense demons, and demon blood. Nero, Crowley, you guys know you go here. Is there anyone else out there with demon blood Dante could sense? Keep in mind that the amount of blood effects what he senses (i.e. He had no idea Nero was there until he came face to face with the kid). Also, Dante won't mention the demon blood unless he's one on one with the person.
2) He can sense if someone's a bit... off. He won't be able to tell if their human or not, but he can definitely tell there's something strange about them. However, he's unable to track them via his weird telepathy/sensitivity thing, and, unless in the same room, doesn't notice them. This would apply to someone like, oh, Danny Fenton, who's part human, but part SOMETHING ELSE.
3) Beings who are SOMETHING ELSE, but powerful enough to shield themselves from Dante's senses. People in this category are gods/goddesses like Dite or Apollo, or beings who have telepathic powers to make Dante think he's just imagining things. If your character falls under here, could you also mention of they would block themselves from Dante's senses, or if they wouldn't bother because of whatever reason?
4) Humans who have powers that stick weird smells on them. For example, someone who turns into a dog a lot would have a certain doggy smell about them, people who shoot lighting would smell like ozone, and a mass murderer who has been drenched in blood more then a few times would have the smell of blood stuck to them.
Thanks again everyone!