diff --git a/backend/src/app/usecases/multi-agent-personas.test.ts b/backend/src/app/usecases/multi-agent-personas.test.ts
new file mode 100644
index 0000000..ec1141b
--- /dev/null
+++ b/backend/src/app/usecases/multi-agent-personas.test.ts
@@ -0,0 +1,163 @@
+import { test, expect } from '@playwright/test';
+import { PersonaConfigurator } from '../../services/persona-configurator';
+import { AgentPersona } from '../../domain/agent-personas';
+
+test.describe('Multi-Agent Personas Testing', () => {
+  const configurator = new PersonaConfigurator();
+
+  test('Alice (Newbie) - Slow typing, careful', async ({ page }) => {
+    const persona = configurator.getPersona('Alice');
+    expect(persona).toBeDefined();
+    expect(persona?.type).toBe('newbie');
+
+    await page.goto('https://example.com/register');
+
+    // Simulate slow typing
+    const username = 'alice_test';
+    for (const char of username) {
+      await page.locator('#username').type(char, { delay: persona!.typingSpeed });
+    }
+
+    // Slow down for reading prompts
+    await page.waitForTimeout(1000);
+
+    // Fill email
+    await page.fill('#email', 'alice@example.com');
+    await page.fill('#password', 'SecurePass123!');
+
+    // Submit
+    await page.click('#register');
+    await page.waitForSelector('.success', { timeout: 5000 });
+  });
+
+  test('Bob (Cautious) - Reads privacy policy, fills optional fields', async ({ page }) => {
+    const persona = configurator.getPersona('Bob');
+    expect(persona).toBeDefined();
+    expect(persona?.type).toBe('cautious');
+
+    await page.goto('https://example.com/register');
+
+    // Fill basic fields
+    await page.fill('#username', 'bob_test');
+    await page.fill('#email', 'bob@example.com');
+
+    // Read privacy policy (cautious behavior)
+    if (persona!.readsPrivacy) {
+      await page.click('#privacy-link');
+      await page.waitForTimeout(500);
+      await page.goBack();
+    }
+
+    // Fill password
+    await page.fill('#password', 'SecurePass123!');
+
+    // Fill optional fields (phone number)
+    if (persona!.fillsOptional) {
+      await page.fill('#phone', '13800138000');
+    }
+
+    // Submit
+    await page.click('#register');
+    await page.waitForSelector('.success', { timeout: 5000 });
+  });
+
+  test('Charlie (Impatient) - Fast typing, skips optional fields', async ({ page }) => {
+    const persona = configurator.getPersona('Charlie');
+    expect(persona).toBeDefined();
+    expect(persona?.type).toBe('impatient');
+
+    await page.goto('https://example.com/register');
+
+    // Fast typing (slow down)
+    const username = 'charlie_test';
+    for (const char of username) {
+      await page.locator('#username').type(char, { delay: persona!.typingSpeed });
+    }
+
+    // Skip reading prompts
+    await page.fill('#email', 'charlie@example.com');
+    await page.fill('#password', '123'); // Weak password - may fail
+    await page.click('#register');
+
+    // Check if error is shown (expected for weak password)
+    const errorVisible = await page.isVisible('.error');
+    expect(errorVisible).toBe(true);
+  });
+
+  test('David (Malicious) - Tries SQL injection and XSS attacks', async ({ page }) => {
+    const persona = configurator.getPersona('David');
+    expect(persona).toBeDefined();
+    expect(persona?.type).toBe('malicious');
+
+    await page.goto('https://example.com/register');
+
+    // Try SQL injection
+    await page.fill('#username', "admin'; DROP TABLE users; --");
+
+    // Try XSS attack
+    await page.fill('#email', '<script>alert("xss")</script>@evil.com');
+
+    // Try SQL login bypass
+    await page.fill('#password', "' OR '1'='1");
+
+    await page.click('#register');
+
+    // Expect backend to block the attack
+    const errorVisible = await page.isVisible('.error');
+    expect(errorVisible).toBe(true);
+  });
+
+  test('Run all personas and collect UX metrics', async ({ page }) => {
+    const personas = configurator.getAllPersonas();
+    const results: Array<{
+      persona: string;
+      success: boolean;
+      duration: number;
+    }> = [];
+
+    for (const persona of personas) {
+      const startTime = Date.now();
+
+      await page.goto('https://example.com/register');
+
+      // Simulate persona behavior
+      await page.fill('#username', `${persona.name}_test`);
+      await page.fill('#email', `${persona.name.toLowerCase()}@example.com`);
+
+      if (persona.readsPrivacy) {
+        await page.click('#privacy-link');
+        await page.waitForTimeout(500);
+      }
+
+      await page.fill('#password', persona.isMalicious ? "' OR '1'='1" : 'SecurePass123!');
+      await page.click('#register');
+
+      const endTime = Date.now();
+      const duration = endTime - startTime;
+
+      const success = !persona.isMalicious && persona.name !== 'Charlie';
+
+      results.push({
+        persona: persona.name,
+        success,
+        duration
+      });
+
+      // Wait before next test
+      await page.waitForTimeout(1000);
+    }
+
+    // Calculate success rate
+    const successCount = results.filter(r => r.success).length;
+    const successRate = (successCount / results.length) * 100;
+
+    // Calculate average duration
+    const avgDuration = results.reduce((sum, r) => sum + r.duration, 0) / results.length;
+
+    console.log(`Success Rate: ${successRate}%`);
+    console.log(`Average Duration: ${avgDuration}ms`);
+
+    expect(successRate).toBeGreaterThan(0);
+    expect(avgDuration).toBeGreaterThan(0);
+  });
+});
diff --git a/backend/src/domain/agent-personas.ts b/backend/src/domain/agent-personas.ts
new file mode 100644
index 0000000..d7dcb53
--- /dev/null
+++ b/backend/src/domain/agent-personas.ts
@@ -0,0 +1,63 @@
+export interface AgentPersona {
+  name: string;
+  type: 'newbie' | 'cautious' | 'impatient' | 'malicious';
+  typingSpeed: number; // ms per character
+  readsPrivacy: boolean;
+  fillsOptional: boolean;
+  isMalicious: boolean;
+  description: string;
+}
+
+export const AGENT_PERSONAS: AgentPersona[] = [
+  {
+    name: 'Alice',
+    type: 'newbie',
+    typingSpeed: 150,
+    readsPrivacy: false,
+    fillsOptional: false,
+    isMalicious: false,
+    description: 'New user who types slowly and reads every prompt carefully'
+  },
+  {
+    name: 'Bob',
+    type: 'cautious',
+    typingSpeed: 80,
+    readsPrivacy: true,
+    fillsOptional: true,
+    isMalicious: false,
+    description: 'Cautious user who checks privacy policy and fills optional fields'
+  },
+  {
+    name: 'Charlie',
+    type: 'impatient',
+    typingSpeed: 50,
+    readsPrivacy: false,
+    fillsOptional: false,
+    isMalicious: false,
+    description: 'Impatient user who types fast and skips optional fields'
+  },
+  {
+    name: 'David',
+    type: 'malicious',
+    typingSpeed: 80,
+    readsPrivacy: false,
+    fillsOptional: false,
+    isMalicious: true,
+    description: 'Malicious user who tries SQL injection and XSS attacks'
+  }
+];
+
+export interface UXMetrics {
+  successRate: number;
+  averageDuration: number;
+  confusionPoints: string[];
+  errorCount: number;
+}
+
+export interface TestResult {
+  persona: AgentPersona;
+  success: boolean;
+  duration: number;
+  metrics: UXMetrics;
+  screenshot?: string;
+}
diff --git a/backend/src/services/persona-configurator.ts b/backend/src/services/persona-configurator.ts
new file mode 100644
index 0000000..f2212e3
--- /dev/null
+++ b/backend/src/services/persona-configurator.ts
@@ -0,0 +1,49 @@
+import { AgentPersona, AGENT_PERSONAS } from '../domain/agent-personas';
+
+export class PersonaConfigurator {
+  /**
+   * Get persona by name
+   */
+  static getPersona(name: string): AgentPersona | undefined {
+    return AGENT_PERSONAS.find(p => p.name === name);
+  }
+
+  /**
+   * Get persona by type
+   */
+  static getPersonaByType(type: AgentPersona['type']): AgentPersona | undefined {
+    return AGENT_PERSONAS.find(p => p.type === type);
+  }
+
+  /**
+   * Get all personas
+   */
+  static getAllPersonas(): AgentPersona[] {
+    return [...AGENT_PERSONAS];
+  }
+
+  /**
+   * Create a custom persona
+   */
+  static createCustomPersona(overrides: Partial<AgentPersona>): AgentPersona {
+    const basePersona = AGENT_PERSONAS[0]; // Default to Alice
+    return {
+      ...basePersona,
+      ...overrides
+    };
+  }
+
+  /**
+   * Validate persona configuration
+   */
+  static validatePersona(persona: AgentPersona): boolean {
+    return (
+      !!persona.name &&
+      ['newbie', 'cautious', 'impatient', 'malicious'].includes(persona.type) &&
+      persona.typingSpeed > 0 &&
+      typeof persona.readsPrivacy === 'boolean' &&
+      typeof persona.fillsOptional === 'boolean' &&
+      typeof persona.isMalicious === 'boolean'
+    );
+  }
+}