The Art of Making Peace with the Devil

Every Devil out there,
Wants to make life a disordered mess,
We don't let them,
Until the Devil outside joined forces,
With the Devil inside.
Oh boy,
Here we go again.

You can't win every Devil there ever is,
You can, however,
Make peace with your inner Devil.
Feed it something, anything,
To keep it inside the cage.
An hour,
A day,
A week,
A month,
A year,
A decade.
Whatever is necessary,
For your sake and mine.

What do you do with an imprisoned Devil?
Observe it, of course!
Note down optimum containment methods,
Best sacrificial material,
Positive and negative side-effects,
Nocturnal activity,
Mental states,
Defense mechanisms,
Memory palace shape,
And other noteworthy abnormalities.
What for, you ask?
To make a manual, of course!
A manual to master,
The Art of Making Peace with the Devil.