A voice guide must describe repeatable language choices. Personality adjectives alone do not tell an editor how to write a line.

Reproducible voice table

Speaker / narrator	Syntax and contraction rate	Diction and address	Emotional behavior	Progression	Avoid
Mina Kurose	complete, compact clauses; few contractions at work	procedural verbs, surnames, precise questions	displaces concern into logistics	shorter and more contracted when frightened	Making every line stiff or clinical.
Ren Saegusa	loose clauses, frequent contractions, comfortable fragments	ordinary concrete words, first names	jokes around fear, then states decisions plainly	loses jokes after the midpoint	Adding slang unsupported by the source.
Aster	balanced clauses, evaluative tags, selective contractions	stylish but not ornate; `あなた` varies by intimacy	exposes hostility through amused judgment	public polish breaks only in private	Feminine pronouns, eye dialect, or a repeated “darling.”
Archive narrator	long observational sentences with careful uncertainty	sensory and temporal vocabulary	withholds conclusions	stable until identity reveal	Upgrading every sentence into ornate literary prose.

Useful English levers

contraction rate and sentence completeness;
clause length, nesting, and preferred connectors;
direct requests versus hedging;
technical, institutional, ordinary, or idiosyncratic vocabulary;
questions, fragments, repetitions, interruptions, and self-correction;
titles, kinship terms, names, and second-person avoidance;
explicit emotion versus displaced description;
public/private, early/late, and calm/pressured code-switching.

Use several subtle levers together. Do not build a voice from one particle, one catchphrase, or an invented accent.

Worked decisions

Situation	Flat or wrong English	Voice-aware English	Decision
Mina gives reluctant permission	“Okay, you can go.”	“All right. Go—but report back by six.”	Complete syntax and procedural framing carry her concern.
Ren sees an obvious disaster	“This situation is very bad.”	“Yeah. This is bad.”	Short, ordinary language fits his tired directness.
Aster dismisses a proposal	“That is a foolish plan.”	“You really do make the most charming mistakes.”	Amused evaluation preserves hostility without caricature.

The good line is not freer because it is more colorful; it is justified by repeated evidence and the current emotional state.

Narrator voice

Give narrators the same treatment as dialogue characters. Record what they notice, how quickly they infer motives, whether they describe bodies clinically or emotionally, and how they handle uncertainty. Blank speaker cells do not imply a neutral house style.

Maintenance

For each rule, keep representative line IDs and at least one counterexample. Update the guide when a later route reveals genuine progression; do not rewrite earlier chapters into the later voice.