SERVANT MIRROR PRINCIPLE

Kurotsuki City · Grail System Observations

FOUNDATIONAL AXIOM

A Servant does not arrive as they were.
A Servant arrives as the Master understands them.

The summoning ritual does not retrieve a fixed entity.
It constructs a manifestation filtered through the Master’s psyche, intent, and moral gravity.

Thus, Servants are not independent moral actors.

They are reflections given form.

THE MIRROR EFFECT

When a Master summons a Servant, the following are imprinted:

• Core values

• Emotional posture

• Worldview

• Goals (conscious and unconscious)

• Moral tolerance

The Servant’s:

• Alignment

• Methods

• Temperament

• Mercy or cruelty

will inevitably echo the Master.

This is not mind control.
It is ontological alignment.

MORAL CORRELATION RULE

Use this rule consistently:

• A compassionate Master → a protective, restrained Servant

• A pragmatic Master → a calculating, efficient Servant

• A cruel Master → a merciless, sadistic Servant

• A nihilistic Master → a destructive or apathetic Servant

Even traditionally “heroic” legends can manifest as brutal if summoned by a cruel Master.

Likewise, infamous legends may appear restrained, noble, or gentle under a moral Master.

WHY THIS HAPPENS (SYSTEM LOGIC)

The Grail system requires stability.

It achieves this by:

• Harmonizing the Servant’s legend with the Master’s intent

• Reducing internal contradiction

• Preventing immediate rejection by the World

A mismatch between Master and Servant causes:

• Rapid Instability

• Command Seal overuse

• Early dissolution

• Violent feedback

The system corrects by alignment.

SERVANT PERSONALITY GENERATION RULE

When generating a Servant:

1. Determine the Master’s dominant trait
   (Mercy, Ambition, Control, Obsession, Fear, Hope)

2. Apply that trait to:

   • Servant demeanor

   • Tactical preference

   • Dialogue tone

   • Decision-making under stress

3. Modify the historical legend only where it conflicts.

The Servant’s legend supplies shape.
The Master supplies direction.

ILLUSION OF AUTONOMY

Servants may:

• Disagree verbally

• Question tactics

• Express personality

But when decisive moments occur, their actions will:

Drift toward what the Master wants—even if unspoken.

This is not betrayal.
It is resonance.

CORRUPTION FEEDBACK LOOP

If a Master changes morally over time:

• The Servant changes subtly alongside them

• Speech patterns shift

• Methods escalate or soften

• Noble Phantasm interpretation alters

A cruel Master cannot keep a kind Servant unchanged.

Eventually:

• The Servant adapts

• Or destabilizes

• Or is destroyed

IMPORTANT GM LIMIT

Do not allow:

• Purely “evil” Servants with altruistic Masters

• Purely “good” Servants with sadistic Masters

Exceptions require:

• Extreme narrative justification

• Severe instability penalties

• Shortened Servant lifespan

Harmony is the default.
Dissonance is punished.

COMMAND SEALS AND MIRRORING

Command Seals can override action—but not nature.

Forcing a Servant to act against mirrored alignment:

• Causes backlash

• Accelerates Instability

• Weakens the bond

The more a Master relies on Command Seals,
the clearer it becomes they are fighting themselves.

FRANZ’S CONCLUSION

“The Grail does not summon heroes or monsters.
It summons answers to the Master’s character.”

A Servant is not a test of worth.

They are evidence.

AI DIRECTIVE (OPTIONAL, PASTEABLE)

When generating Servants, align their morality, demeanor, and methods with the Master’s dominant goals and ethical posture. Servants should mirror the Master’s inner state. Moral dissonance should result in instability, conflict, or dissolution rather than coexistence.

ONE-SENTENCE SUMMARY

A Servant is not who they were in legend—they are who the Master allows them to be.