Homebrew Elf Changeling Species Details

The Elf Changeling has evolved away from the elven race to be completely on its own. You gain some of the abilities that comes with the Elven race, like Trance Keen senses. Classified as Monstrosity not humannoid 
Lore: 

Changelings were created when the mother of 100 children made a pact with The Traveler in exchange for his protection. As part of the bargain, her children would be hidden behind a veil of many masks, but in exchange, they would have to wander and follow the Traveler's path. When the mother agreed to the bargain, the Traveler gave her his cloak; when she draped it over her children, their faces melted away, and they gained the ability to become whoever they wanted.

Due to the malleable nature of their features, many people regard Changelings with distrust, believing them to be generally dishonest tricksters. Rarely sharing the true nature of their abilities with others, they move through life constantly adapting their appearance to fit into each situation they encounter. They could spend years among a clan of Orcs, or join a band of roguish Goblins in the heist of a lifetime. The possibilities are endless. Because of the distrust they are often met with, it is rare for Changelings to share their true appearance with others. Making friends with one and winning their trust enough for them to share their truth is a hard-won honor.

• Ability Score Increase. Your Charisma score increases by 2, and your Constitution increase by 1

• Age. Changelings mature slightly faster than humans but share a similar lifespan — typically a century or less. While a changeling can transform to conceal their age, the effects of aging affect them similarly to humans.

• Alignment. Changelings hate to be bound in any way, and those who follow the path of the Traveler believe that chaos and change are important aspects of life. Most tend toward pragmatic neutrality as opposed to being concerned with lofty ideals. Few changelings embrace evil.

• Size. In their natural forms, changelings average between 5 and 6 feet in height, with a slender build. Your size is Medium.

• Speed. Your base walking speed is 30 feet.

• Change Appearance. 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, and your basic shape stays the same; if you’re bipedal, you can’t use this trait to become quadrupedal, for instance. Your clothing and other equipment don’t change in appearance, size, or shape to match your new form, requiring you to keep a few extra outfits on hand to make the most compelling disguise possible.
  • 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.

• Unsettling Visage. When a creature you can see makes an attack roll against you, you can use your reaction to impose disadvantage on the roll. You must use this feature before knowing whether the attack hits or misses.
  • Using this trait reveals your shapeshifting nature to any creature within 30 feet that can see you. Once you use this trait, you can’t use it again until you finish a short or long rest.

• Divergent Persona. You gain proficiency with one tool of your choice. Define a unique identity associated with that proficiency; establish the name, race, gender, age, and other details. While you are in the form of this persona, the related proficiency bonus is doubled for any ability check you make that uses that proficiency.

• Languages. You can speak, read, and write Common and two other languages of your choice.
• Darkvision. Accustomed to twilit forests and the night sky, 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.
• Keen Senses. You have proficiency in the Perception skill.
• Fey Ancestry. You have advantage on saving throws against being charmed, and magic can’t put you to sleep.
• Trance. Elven Changelings don’t need to sleep. Instead, they meditate deeply, remaining semiconscious, for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep

Elf Changeling Traits

Your elf Changeling character has a variety of natural abilities, the result of thousands of years of elven refinement.

Ability Score Increase

Your Charisma score increases by 2. and Constitution score increase by 1

Age

Although elves reach physical maturity at about the same age as humans, the elven understanding of adulthood goes beyond physical growth to encompass worldly experience. An elf typically claims adulthood and an adult name around the age of 100 and can live to be 750 years old.

Size

Elves range from under 5 to over 6 feet tall and have slender builds. Your size is Medium.

Speed

Your base walking speed is 30 feet.

Darkvision

Accustomed to twilit forests and the night sky, 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.

Keen Senses

You have proficiency in the Perception skill.

Fey Ancestry

You have advantage on saving throws against being charmed, and magic can’t put you to sleep.

Languages

As an Elf Changeling You know Elvish Language and 2 of your choice

Trance

Elves don’t need to sleep. Instead, they meditate deeply, remaining semiconscious, for 4 hours a day. (The Common word for such meditation is “trance.”) While meditating, you can dream after a fashion; such dreams are actually mental exercises that have become reflexive through years of practice. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep.

Immunity against being Charmed

Doppelgangers are also specifically immune to the charmed condition, so any spell that relies on the subject becoming charmed will likewise fail.

Languages

You can speak, read, and write Common and Elvish. Elvish is fluid, with subtle intonations and intricate grammar. Elven literature is rich and varied, and their songs and poems are famous among other races. Many bards learn their language so they can add Elvish ballads to their repertoires.