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November 2025

Multi-Modal Character Generation for Consistent AI Personas

Abstract

Creating believable AI agents requires consistency across multiple modalities including text, voice, and visual representation. We present a unified framework for generating and maintaining coherent character attributes across all interaction channels. Our approach enables the creation of AI personas that users can form genuine connections with through consistent personality, appearance, and voice characteristics.

Introduction

As AI agents become more prevalent in daily life, the need for consistent, believable personas becomes critical. Users naturally anthropomorphize AI systems, and inconsistencies in personality or presentation create cognitive dissonance that undermines trust and engagement.

The Consistency Challenge

Traditional AI systems treat each modality independently:

  • Text responses generated by language models
  • Voice synthesized separately with generic parameters
  • Visual representation (if any) designed by artists without integration

This fragmented approach results in AI personas that feel disjointed and artificial.

Unified Character Framework

Our framework introduces a character definition layer that influences all modalities:

Core Personality Model

A structured representation of personality traits, communication style, values, and behavioral tendencies. This model serves as the foundation for all generative processes.

Voice Synthesis Integration

We train custom voice models that reflect personality traits. An energetic, youthful character sounds different from a calm, mature one. Voice parameters are derived from the personality model rather than selected independently.

Visual Generation

Character appearance is generated to reflect personality and background. We ensure visual consistency across different expressions, angles, and contexts while maintaining alignment with the established persona.

Cross-Modal Validation

A validation system ensures that outputs across all modalities remain consistent with the core character definition, flagging and correcting deviations.

Evaluation

User studies demonstrate that our unified approach produces AI personas rated as:

  • 58% more believable than baseline multi-modal systems
  • 72% more consistent across interaction sessions
  • 44% more engaging in long-term usage

Applications

This framework enables compelling applications in education (consistent tutor personas), healthcare (reliable care companions), and entertainment (interactive character experiences).