D&D 5E (2014) Help with creating tiefling for 5e campaign

[lapizlizard]

fluff me this. teifling mestophielias wild magic sorcerer who was trapped in a room in his parents noble castle (king and qeen)

I know their is a lot here, but please help. if you need their appearance, they are pure white with gold chaotic patterns, swirling around thier eyes. alignment chaotic good.

 

[Burnside]

1. Was there a horse that broke the camel’s back incident that caused the family to lock the tiefling away a la Rain Man?

2. Who was the one character who visited and was tiefling’s friend/sympathizer?

3. Personality flaw caused by isolation? This situation could cause agoraphobia, social anxiety, and a bunch of other issues

4. Was tiefling “replaced” in the family by a more acceptable child - perhaps one who was adopted for that specific purpose?

5. How did the confinement end?

6. What is current status of relationship to family?