Wings are sometimes present on incubi/succubi, and if they possess wings, they are able to fly using them.

Half-Breeds will tend to look like the other species they are joined with, as the incubi/succubi have no real "look" to them, as they are non-corporeal.

People who can sense energies and such, will be able to sense the sexuality of these creatures surrounding them. They are usually extremely attractive, and can easily have people fall over each other trying to get to know them. They are, all in all, sexual creatures, and use this to their greatest advantage.

Characteristics
Incubi/Succubi are extremely sexual in nature. They will do everything possible to bed a certain person, and there are quite a lot of romantic stories about these creatures. They lust easily, and will pursue those people till the ends of the earth. Once the sexual act is committed, they usually lose interest and will drop them to find someone new.

Generally well tempered, perhaps a bit to forward in their speech, these demons hardly let anyone get to know their true selves. They are reclusive, when not persuing someone.

Half-breeds have other characteristics.

Due to the nature of the Incubi/Succubi being normally non-corporeal, they barely retain anything that would categorize them as such. They also tend not to know that they are half incubus/succusbus, and consider themselves the species of the parent that raised them. A few clues do remain of their true heritage:

Half-breeds aren't as sexual as their full blooded counterparts. They do exude pheremones, to attract others, but they have no way of controlling this. This simply happens, much to the dismay of the half-breeds, but usually in the presence of those they are attracted to. They tend to be severely reclusive because of this, and tend to shy away from social gatherings. It is possible to cover up the pheremones by wearing cologne or simply by not bathing for awhile. Also, they offset some of the weaknesses from their joined race, as Incubi/Succubi have none, except those that any normal human or lesser demon would (hellfire, nightvision, etc). If you are creating a half-breed, you can't go all out and completely nullify a weakness, you would have to work out something that lessens an affect.

They can fly, have nightvision, and are capable of psychic forces, given that they have been able to study them properly. They are quick on their feet, beguiling and are experts on seduction to the point of semi-hypnosis (or 'charming' their victim).

Lifestyle
They eat, sleep and do as anyone else. The main thing that stands out is that they are never sexually satiated, they're always ready for sex. Non-corporeal tend to be rapists, but those that possess a physical body will go on dates, seduce, beg or do whatever it takes to get their prey into their grasp. They feed upon sexual energy through the sexual act. Usually completely draining the other of their energy, leaving them breathless and extremely weak.

Artwork: Marcos Jardim, Succubus [Website]