A short treatise on mental defense, by Luna

A/N: This is from an earlier time in my alternate history when Equestria was at war with other nations. 'Person' was a word widely used, and Luna was never happy with it having fallen out of favor.

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Defense is always easier than attack. This is seen again and again throughout the world; a weapon must be specially crafted to destroy or bypass plate armor, a hundred mares can stand against a thousand when holding a wall, and even the weakest mage or mentalist can fend off a skilled practician of their art long enough for help to arrive. This is a natural law of the world, for if it were not so civilization would not be possible.

So it is that anyone could use the following rules to resist mental intrusion. And I do mean anyone. A popular sport for two dueling mentalists in the barracks is to find a proxy—a completely uneducated peasant—and teach them the basics of mental defense in one hour. If the proxy withstands ten minutes of mental assault, their sponsor wins. One hour. That is all it takes.

Once a mindscape is established, one can build their defenses simply by imagining them into existence. Walls are a popular choice, and for good reason. But there are some ambitious beginners who begin imagining complex indestructible domes of energy, or invisible mazes that lead nowhere. If these newcomers have a capable teacher, these defenses are torn down with ease, and all the aspiring mentalist suffers is humiliation. The self-taught variety often undergo this experience at the hands of one who is willing and able to tear their mind apart.

The first principle one must internalize is this:

Attackers play at your level.

Indestructible energy shields lead to teleporting arrows that explode on impact. The simple wall restricts an intruder to rope and will. Everything must be plausible. A castle must have a gate, ladders, and normal geometry. Four-dimensional mazes lead to four-dimensional tunnels. Deny the intruder every advantage of experience. Remove any opportunity for out-of-the-box thinking. You could be the most imaginative person in the world, but a skilled mentalist has time, practice, and reflex for every opportunity presented to them.

In the realm of mind, everything is possible. Everything is easy. Perhaps you're clever, and thought: "Ah, but a castle must be defended," and then went on to create an entire army. Your opponent will use this against you. Your army's mind is your unconscious one. An untrained mind is irrational and easily distracted. Meanwhile, you free your opponent to create their own army from their own heavily disciplined mind; brutal golems of destruction that will overpower you in seconds.

You will be vulnerable in sleep. If you are truly at such risk that your mind must be guarded at all times, these instructions are not adequate for defense. You will need to become competent. Good luck.