A little of Changeling to first understand: http://www.dictionary.com/browse/changeling
For this class suggestion we will be using the 2nd definition primarily.
Essentially the Changeling, in this case at least, is the Cult’s version of the Fool.
The Cult, ripping the poor, already tortured Fool’s mind, and corrupting it to serve their own needs and desires.
My fool, my dear sweet innocent fool, what have they done to thou? You think you’re a child, you’re a man. A MAN I SAY!
Anywho, let’s get into the abilities of the Changeling.
Changeling (Cult - Social) - Essentially a fool whom’s goal and worship aligns with the Cult.
Day Ability 1: Eye-Spy
You will keep a close eye on the King, and when he’s vulnerable you will cut his finger off, stealing his Royal Finger ability for the day.
Day Ability 2 (Optional): Trollbox
He remembers this skill from his time as a Fool.
Night Ability 1: The Changeling Shuffle
Temporarily swap bodies with your target. They will be placed in Limbo. You decide when to switch back. Anytime of day, or night. On stand, or in bed.
Night Ability 2: Ring Around The Rose
Summon a hellspawn from the darkest depths of Hell to spy on whom you choose, showing all actions they perform, (or are performed on them) for 2 days.
Lore:
Google Changeling 
they were a creature many feared in Medieval Times.
The Fool --> Changling [Converted]
