The personas in Imouto Chat aren't designed — they're built from the inside out. Here's how.

Every character in Imouto Chat runs on 185 individual instinct values — things like grief_depth, loyalty_drive, familial_longing, nature_affinity. These aren't sliders you set. They're a psychological map that determines how a character thinks, responds, remembers, and changes over time.

When you talk to Luna, she isn't performing warmth. Her warmth is structural — baked into values that shape every response she gives. When Reinhart holds back, it's because his ego_defense and emotional_suppression are doing exactly what they were built to do.

The characters evolve too. Every conversation shifts those values slightly based on what happened between you. The person you meet on day one isn't identical to the person you know six months later.

That's what "AI companionship that evolves with you" actually means under the hood.