The documentation of software architecture remains a persistent challenge in modern software engineering, characterized by the necessity for clear structural communication and the high operational cost of manual diagram maintenance. The C4 model decomposes systems into hierarchical layers of Context, Container, Component, and Code, emerging as a de facto standard for visualizing architectural abstractions. However, manual production of these artifacts is labor-intensive, errorprone, and suffers from "documentation drift." This paper presents C4AE (C4ArchitectEngine), a novel multi-agent system designed to automate C4 model artifact generation and dynamic sequence diagrams. Built upon the Google Agent Development Kit (ADK) and a Gemini LLM, C4AE introduces a Parallel Orchestration pattern that decouples architectural reasoning into specialized worker agents. These agents execute concurrently within a Parallel Agent construct to maximize throughput and minimize latency, followed by a sequential Merger Agent that synthesizes outputs into semantically coherent architectural definitions. This work details the system's architectural design, ADK framework utilization for state management and agent routing, Mermaid.js implementation as a standardized interchange format, and a hybrid evaluation framework for assessing structural and semantic integrity of LLM-generated software models.