Your Charisma score increases by 2, and your Dexterity score increases by 1. 

Succubi/Incubi are ageless demons, typically reaching adulthood between the ages of 15 and 19 and will not die of old age.

Due to their fiendish natures, succubi and Incubi often tend toward evil alignments. Neutral or good succubi are extremely rare, but not unheard of. They have no particular tendency toward or against lawful or chaotic alignments.

Succubi and Incubi range from barely 5 feet to well over 6 feet tall. Regardless of your position in that range your size is Medium.

Your base walking speed is 30 feet.

You have a flying speed of 30 feet. To use this speed you can’t be wearing heavy armor. Also you cannot end your turn in the air if you are wearing medium armor, you must land or otherwise keep yourself aloft or you will fall to the ground at the end of your turn. If you are wearing light armor or no armor you can stay in the air at the end of your turn.

Because you are a fiend, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

Your creature type is considered to be both Fiend and Humanoid, and you are considered to have the Shapechanger tag. Additionally, you are vulnerable to radiant damage.

As an action, you can polymorph into any humanoid of your size that you have seen or back into your true form. However, your equipment does not change with you. You lose the fly speed trait if your current form does not have wings. If you die, you revert to your natural appearance. Your attributes are unaffected by this change. 

You have proficiency with the Persuasion and Deception skills.

You can cast the charm person spell once using this trait, using Charisma as your spellcasting ability. You regain the ability to cast this spell when you finish a long or short rest.

The Succubis/Incubus can telepathically communicate with a creature it has charmed, there is no range limit on this bond. The two don't even need to be on the same plane of existence.

The Succubus/Incubus kisses a creature charmed by it or a willing creature. The target must make a Constitution saving throw against your Charisma Spell Save DC (8 + Charisma + Proficiency), taking 1d10 + Charisma Modifier psychic damage on a failed save, or half as much damage on a successful one, the number of dice used to calculate this damage increases by one at levels 5 (2d10), 10 (3d10), 15 (4d10), and 20 (5d10). The target's hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest or the Succubus/Incubus that performed it is killed. After the target takes damage from this attack it can make a saving through with advantage against any charming effects you have on it. The target dies if this effect reduces its hit point maximum to 0.

The Succubus/Incubus magically enters the Ethereal Plane from the Material Plane, or vice versa. Starting at level 13 you can cast the spell Etherealness on yourself once per long rest. 

You can speak, read, and write Common, Abyssal, and Infernal.