Imposter

You are no one and everyone. The Impostor has dedicated
their lives to inhabiting someone else. They have followed
and studied all different races and cultures in their travels.
They have analyzed heir appearance and quirks, their gate
and speech patterns, and the sound of their voice. The
Impostor keeps these little subtitles and uses them as a
weapon. They get to the core of who a person is and dissects
them in order to lie their way into getting what they want.
The Impostor has mastered their craft to the point that their
close friends and allies might not even know who they truly
are.

Tools of Deception

At level 3 once you have decided that you want to be anyone
you see then the work begins. You have studied and observed
and learned the tricks of your trade.

In someone else's shoes

•  You gain the ability to create a disguise very quickly. On a
  successful stealth roll you may also apply a disguise on
  the same action. If you take the hide action you may also
  use your disguise kit as a bonus action. These are basic
  disguises only. You can not create a disguise for anything
  that is a size larger than you. Disguises can only be made
  of someone or something with a humanoid form. This can
  include demons or fey. It is up to the DM's discretion who
  or what you may impostor.
• The impostor can take an 10 minutes to create a flawless
  disguise. It can only be based on someone they have
  studied for at least 1 minute that week. Given the time and
  materials the impostor is able to completely replicate a
  person they want to impersonate. All perception checks to
  see through the disguise are done at disadvantage. You
  can create a flawless disguise a number equal to your
  charisma modifier per day.
• You gain advantage on charisma (deception) and charisma
  (performance) checks while in a flawless disguised.

Friend or Foe?

• At level 9 you are now able to utilize your mimicry skills on
  the battlefield. You gain the ability to create disguises at
  lightning speed and move your way through the battlefield.
  You may use your action to create a hasty disguise of a
  creature on the battlefield that you can see. If you are
  hidden it can be done as a bonus action.
• While you are disguised, allies of the person you are
  disguised as become hesitant to attack you. When such a
  creature targets you with an attack while it is within 15
  feet of you, you can use your reaction to attempt to sway it.
  The creature must make an Intelligence (Investigation)
  check (DC 8 + your proficiency bonus + your Charisma
  modifier). If you are wearing a disguise created with your
  Flawless Disguise feature, the check is made with
  disadvantage. On a failed check, the creature must choose
  a different target, or the attack automatically misses. You
  can use this reaction a number of times equal to your
  Charisma modifier, and regain all expended uses when
  you finish a long rest.
• If you are disguised as a creature then you may attempt to
  hide in plain sight. As long as you are within 15 feet of an
  attacking creature and there are multiple opponents you
  may try to appear as an opponent's ally. You may roll
  deception instead of stealth to hide and you do not have to
  be behind any sort of cover

In the heat of battle

• You may now create a battle disguise as a bonus action.
• Your words and actions are so convincing that you can
  compel others to believe that someone else is the
  impostor. When an opponent begins their turn within 15
  feet of you and you are wearing a disguise you have the
  chance persuade them to attack another ally that is within
  15 feet instead. You must make a charisma (persuasion)
  roll and the enemy must make an opposed Wisdom
  (Insight) check. If you are wearing a flawless disguise then
  you roll with advantage. If successful the opponent moves
  and attacks the enemy you are disguised as instead of you.
  You may do this an amount of times equal to your
  proficiency modifier per long rest.
• You have become a master at blending into battle. When
  you use your deception to hide you may add your
  charisma modifier to the roll.

Thief’s ReflexesLike looking in a mirror

• You have become a master of disguise. You may make a
  perfect replica of the person's face and clothing at only a
  small glance. You may create your flawless disguises as a
  bonus action.
• Now you may use your in the heat of battle ability with an
  enemy who is within 30 feet of you and they can attack an
  enemy that is 30 feet away from them.
• You may now hide in plain sight within 30 feet of your
  enemies.
• You gain expertise with your disguise kit and deception