You came in contact with an arcane spellcaster once, although that encounter might have taken place before your birth. By the mysterious ways of arcane forces, some of the spellcaster's power unnoticedly transferred onto you, imbuing you with the blessing and curse of arcane energy.
That event left you with an unusual connection to arcane energy and the magical and nonmagical creatures around you, allowing you to understand them and use their powers to your advantage.

Alien Powers

The spellcaster your powers diverted off left a lasting mark regarding your spellcasting ability. Up to two of your known spells may originate from the spell list of the spellcaster your powers originate from, instead of one from the sorcerer spell list.
You are also very susceptable to the structure of magic that affects you. When you are affected by a spell, you gain a sudden and short-lived understanding for that spell, allowing you to cast it once until the end of your next round using a spell slot elegible for that specific spell. You may cast it in the timeframe the spell intends (eg. action, reaction, 1m , 10m) and you may keep casting it for its entire duration, even if that extends beyond the end of your next round.

Bard's Mark

You syphoned your powers off a bard. This will later affect your spell options.

Druid's Mark

You syphoned your powers off a druid. This will later affect your spell options.

Pure Sorcerer

You syphoned your powers off a sorcerer. This will later affect your spell options.
! This option limits your spell choices !

Ranger's Mark

You syphoned your powers off a ranger. This will later affect your spell options.

Wizard's Mark

You syphoned your powers off a wizard. This will later affect your spell options.

Versatile Adaptability

Starting at 1st level, you learn how to utilize your special bonds to your surroundings and exploit the power and predict the actions of others.
You gain further abilities on 3rd, 5th, 7th and 9th level.

Adapt and Improve

From 9th level onward, if you encounter a creature that takes multiple attack actions on you in a round, you may take an attack action against that creature as a bonus action in your next round if you first use your normal attack action against that creature.

Imitator's Sense I

At 1st level, due to your special connection to the creatures around you, you know how to convincingly impersonate someone, and you notice unusual happenings. You are a proficient in performance and insight.

Imitator's Sense II

At 3rd level, you learn to calculate your opponent's actions even after briefly observing them. An opponent who attacks you multiple times with the same attack has disadvantage on the attack rolls against you until attacking with another weapon or attack. (Alternatively +2 AC ?)

Recreative Casting

At 7th level you have gained a certain amount of control over the spark of magic inhabiting you. You may use your powers of imitation to imitate a spell you came into contact with, either being affected by it or observing someone casting it. Choose a spell of level 4 or lower from a list of up to 10 spells selected by your DM and roll a d20. If the result is lower or equal to your level, you cast that spell. If not, your action is wasted. After using this ability, regardless whether the chosen spell came into effect or not, you may not use it again until finishing a long rest.

Strong Bonds

At 5th level, you gain the ability to form a bond with one of your party members. You gain their proficiency bonus on one of their proficient skills, and gain half your proficiency bonus on one of your proficient skills. The values are rounded down. If that party member is prone or restrained, you have disadvantage on attack rolls, and if they are frightened, incapacitated or suffer from exhaustion level 4 or more, you have disadvantage on attack rolls and ability checks.
The bond ends if one of you dies, removing all effects.

Powerdrain

At 6th level, you may attempt to cast a spell using a spellslot of another creature. To do so, you need to touch that creature and yourself have a spellslot available to cast the spell you want to cast. You have to specify at which level you want to cast that spell, and expend one sorcery point to use a spell slot up to 3rd level, and 2 sorcery points to use a spell slot of 4th level or higher. An unwilling creature will make a wisdom (WIS) saving throw. If it fails that saving throw, or if it is willing, and it has an available spellslot of the chosen level, you cast the spell, consuming that spell slot. If there is no spell slot available at that level, a spell slot of the next lower level is used. If there is no spell slot available to cast the spell at the chosen level or below, your spell slot is consumed and you cast the spell. If the creature succeeds on the saving throw, you use your spell slot to cast the spell, but take half the damage your target takes, given it is a damage spell. Else you take 1d6 psychic damage which cannot be reduced in any way.

Extract Energy

You have learnt to syphon power from your surroundings. At 6th level, you gain the ability to cast any level of your spells with a spell slot 1 level lower than otherwise required. You may also cast a 1st level spell without using a spell slot. Everything in a 5-foot-radius around you withers, any living non-magical creature in that space has to make a wisdom (WIS) saving throw or take 1d4 necrotic damage, any living magical creature in that space takes 1d8 necrotic damage, or half as much on a successful save. You too take damage: Each time you cast a spell using Extract Energy without taking a long rest, you take 1d8 more necrotic damage, starting at 1d8. On a successful save, you take half as much. If that damage incapacitates you, you do not cast the spell. You cannot cast the spell as a level higher than your highest-level spell slot.

Master of the Unknown

At 14th level, you mastered the arts of imitating other spellcasters and drawing off their knowledge. After copying a spell, you may expend 6 sorcery points to temporarily add it to your list of known spells. It will be available until you take a long rest or choose to do the same with another spell.

[lvl 18 Placeholder Feature, tbd]

At level 18, [Placeholder Description, this feature is absolutely awesome and you can do a lot of great things with it, yeah!]