Taken from Dungeon Master's Guide, pages 286/287:
"Whereas tieflings have fiendish blood in their veins, aasimar are the descendants of celestial beings.These folk generally appear as glorious humans with lustrous hair, flawless skin, and piercing eyes. Aasimar often attempt to pass as humans in order to right wrongs and defend goodness on the Material Plane without drawing undue attention to their celestial heritage."

Stats
+2 Charisma
+1 Wisdom
Medium
Speed 30 feet
Darkvision
Resist Necrotic
Resist Radiant
You know the Light cantrip.
At level 3, you can cast Lesser Restoration once. This ability recharges after a long rest.
At level 5, you can cast Daylight once as a 3rd level spell. This ability recharges after a long rest.
Charisma is your spellcasting ability for these spells.
Languages: Common and Celestial

Obed Olmstead
Race/Class: Half-Elf Warlock 2
Alignment: Chaotic Neutral
Background: Sailor
Languages: Common, Elvish, Halfling

Saving Throws: Wisdom, Charisma
Armour Class: 14
Hit Points: 18
Speed: 30 feet

Str: 12 (+1)
Dex: 16 (+3)
Con: 14 (+2)
Int: 8 (-1)
Wis: 10 (+0)
Cha: 16 (+3)

Skills
Athletics, Acrobatics, Nature, Arcana, Perception, Survival

Racial Features
Darkvision: 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.
Fey Ancestry: You have advantage on saving throws against being charmed, and magic can’t put you to sleep.
Skill Versatility: You gain proficiency in two skills of your choice. (Acrobatics, Survival)

Class Features
Weapon and Armor Proficiencies: Light Armor, Simple Weapons
Skill Proficiences: Nature, Religion
Otherworldly Patron: The Great Old One
Expanded Spell List: dissonant whispers, Tasha's hideous laughter, detect thoughts, phantasmal force, clairvoyance, sending, dominate beast, Evard's black tentacles, dominate person, telekinesis
Awakened Mind: Starting at 1st level, your alien knowledge gives you the ability to touch the minds of other creatures. You can communicate telepathically with any creature you can see within 30 feet of you. You don’t need to share a language with the creature for it to understand your telepathic utterances, but the creature must be able to understand at least one language.
Pact Magic: Your arcane research and the magic bestowed on you by your patron have given you facility with spells. Charisma is your spellcasting ability for your warlock spells.

Background
Skill Proficiencies:: Athletics, Perception
Tool Proficiencies: Navigating tools, Vehicles (Water)
Bad Reputation: No matter where you go, people are afraid of you due to your reputation. When you are in a civilized settlement, you can get away with minor criminal offenses, such as refusing to pay for food at a tavern or breaking down doors at a local shop, since most people will not report your activity to the authorities.

Equipment
A light crossbow and 20 bolts, a component pouch, a dungeoneer's pack, leather armor, spear, two daggers, a belaying pin (club), 50 feet of silk rope, an idol of a nightmarish monster that gives you nightmares when you sleep next to it, a set of common clothes, fishing tackle, bottle of fine wine, steel mirror, and a belt pouch containing 54 gp.

Known Spells
Cantrips: Eldritch blast, minor illusion
1st Level: Hex, Tasha's hideous laughter, hellish rebuke

Eldritch Invocations
Armor of Shadows: You can cast mage armor on yourself at will, without expending a spell slot or material components.
Mask of Many Faces: You can cast disguise self at will, without expending a spell slot.

Weapon Attacks
Spear Attack: 1d6 piercing, thrown (20/60), versatile (1d8)
Crossbow Attack: 1d8 piercing, ammunition (80/320), loading, two-handed
Dagger Attack: 1d4 piercing, finesse, light, thrown (20/60)

Personality
Trait: To me, a tavern brawl is a nice way to get to know a new city.
Ideal: Freedom. The sea is freedom—the freedom to go anywhere and do anything.
Bond: I am the only survivor of a shipwreck and others believe me to be cursed.
Flaw: Once I start drinking, it’s hard for me to stop.

Appearance
Obed Olmstead carries a haunted look of a man wasting away. Though still his body still carries the strength and bulk of a sailor, it has seen better days. He's less toned and he's starting to grow a little beer belly. Dark circles never seem to leave his gray eyes, and his black hair and short beard are already seeing light streaks. His hair is long enough to cover the slight point of his ears and curls when wet. His hands are calloused heavily, and no matter how drunk he gets, Obed's legs remain steady. Across his chest is a line of circular scars.

Backstory
Obed Olmstead had always loved the sea. He grew up a wharf rat, the bastard son of a bitter woman, and he quickly found his way on ships since age 11. At sea, he was free from the strict eye of his mother, the beatings of the city watch who didn't care for urchins, and the despair of poverty. He lived and worked as an equal to the other crew members and authority was hard-earned by the captain, not bought or inherited. More than any other sailor, Obed loved spending time in the water, retrieving goods or fallen crew, exploring, or just spearing dinner.

As he grew up strong with the charm of a half-elf, Obed would attract attention at various harbors, but nothing could beat the allure of the sea for him. Until one day, the sea turned against his ship. The storm was not particularly strong, there have been bigger and stronger storms, but somehow the hull was cracking and the ship was rapidly taking on water. Then, a wave rose far above the ship and as Obed looked up, he swore he saw a writhing figure's silhouette in the wave.

He dreamed, of a beautiful creature who seemed to envelop him into her embrace. Though she looked the size of him, he knew she was vast, that the coiling and stretching darkness around them was a part of her, that her waters sank far below, deeper than any dwarf mine or buried titan. And though she looked the age of him, he knew she was older than storms or earth, older than any god that claimed to rule her, that she was an eternal ocean who would drown and swallow even the sun and moon in time. He opened his mouth to beg her to marry him, and his lungs began to fill with saltwater, and in his soul, she laughed without joy or understanding.

Obed woke up on the beach of his hometown. Everyone suspected the worst because the ship was due to arrive a month ago, so they were shocked to find the sole survivor washed up on shore, especially when according to Obed, the ship was still far out to sea when it sank. Of course, Obed wanted to continue returning to the open ocean, but people have noticed the change in him. Other sailors called him cursed and refused to accept him onto any of their crews and new ships are quickly warned of the man sworn to the sea's cold grasp.

So he drinks and gets thrown out of bars for rowdiness, and he researches and gets thrown out of temples for heresy. He wanders, sometimes with others, to learn more of his mistress, and until he can return to her, he will ply her dark gifts.