For whatever the reason, you’re not even in the body that you were born into. Basically, your soul has been departed that the body and also taken another. So, this may have happened deliberately or else by an accident. Anyway it may have been a punishment of a kid. Of course whatever the reason, that you now inhabit this body and also it is up to you like to how you react.
Skill Proficiencies: Arcana, Insight, Deception
By Inhabiting an another body has been given you the unique understanding of others, even though as well as the ability to hide this particular fact from others. You shall gain the proficiency in Insight & Deception.
However, the use of magic within your transformation has been given you an innate knowledge of all the other things magical. You shall be gaining proficiency in an Arcana.
Tool Proficiencies: You would gain 2 tool proficiencies – which is one related to your original form and also one is related to your new body.
Languages: One of your choice.
Equipment: Here a scroll case has been stuffed full of notes from your studies into your condition (either furthering or returning to your own body), Common;set of common clothes[/item], and 5 gp.
Feature: Arcane Insight
It has been given your unique situation, you are simply able to identify if a person or even a creature has been touched by the magic.
However you can tell if someone is under an influence of an arcane if you spend 10 minutes or else more in the conversation with you. Al though you can simply tell that they have been affected by the magic, but not what the school of magic, or else which particular spell.
Also you are unable to identify if they cast the spell on themselves or else if it was cast by another person. You are also able to identify what type of body parts the spell is affecting (Such as a psychic defense spell creating an arcane trace around a head, or a charisma based enchantment covering only the mouth).
Just there are few questions to ask such as:
Is your one goal to return to your body by any means? Do you seek revenge if this was done against your will? If it was an experiment you undertook willingly, are you hoping to further your research? Discuss with your DM how this happened to you and how you can build it into your world.
As a bonus idea, what happens when this corporeal form is destroyed? Do you die as normal, or do you try and wander to a new body? What happens if you take on the form of another?
Do you battle for the body? Are they forced out into nothingness? Could they try and seek you out for stealing their body? This is another aspect to discuss with your DM. Do you make a series of contested skills checks to see if you are successful in your attempted takeover?