Thanks to your infernal blood, 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. In darkness, you only see in shades of grey.

You start with a -2 penalty to all ability scores

Your Charisma score increases by 2.

You gain +1 to an ability score of your choice. You gain an additional +1 to an ability score of your choice whenever you gain a level.

Newly formed Chosen retain aspects of their original alignment, though as a result of their transformation, and removal of their soul. They will lack things such as empathy and compassion, and will gradually drift towards evil. Also as a result of their patron devil holding dominion over them, excessive displays of neutral or chaotic behavior will result in penalties and possibly demotion depending on the frequency and severity of their actions.

Chosen begin as small but once their transformation is complete they retain their original size, unless specified in their transformation specifically

You gain proficiency with the following two skills: Deception and Persuasion.

You know the thaumaturgy cantrip. When you reach 3rd level, you can cast the hellish rebuke spell as a 2nd-level spell once with this trait and regain the ability to do so when you finish a long rest. When you reach 5th level, you can cast the darkness spell once with this trait and regain the ability to do so when you finish a long rest. Charisma is your spellcasting ability for these spells.

You have resistance to fire damage and immunity to the River Styx.

If a devil dies somewhere other than the Nine Hells, the body disappears with a flash of fire, a puff of smoke or dissolves into a pool of ichor and re-forms in the Nine Hells, it is therefore not truly killed. However, a devil killed in the Nine Hells is dead forever; not surprisingly, that’s why devils tend to be more cautious in their dealings at home than abroad.

As an action, you can transform your appearance or revert to your natural form. You can’t duplicate the appearance of a creature you’ve never seen, and you revert to your natural form if you die.

You decide what you look like, including your height, weight, facial features, the sound of your voice, coloration, hair length, sex, and any other distinguishing characteristics. You can make yourself appear as a member of another race, though none of your game statistics change. You also can’t appear as a creature of a different size than you (withing reason), and your basic shape stays the same; if you’re bipedal, you can’t use this trait to become quadrupedal, for instance. You also decide if your clothing and other equipment also change in appearance. You decide what your clothing and equipment look like. size, shape, material, colour, and any accessories are made up from your equipment.

Even to the most astute observers, your ruse is usually indiscernible. If you rouse suspicion, or if a wary creature suspects something is amiss, you have advantage on any Charisma (Deception) check you make to avoid detection.