《勇者鬥惡龍10 沉睡的勇者與指引的盟友 Online》（ドラゴンクエストX 眠れる勇者と導きの盟友 オンライン）是《勇者鬥惡龍X》這款線上RPG的第二部大型擴充資料片，由Square Enix開發並發行，於2013年12月在日本登陸Wii、Wii U與Windows平台。延續前作的世界觀，並加入全新劇情章節與地圖、角色職業、系統功能等，為整體遊戲體驗帶來顯著深化與進化。

故事背景延續主線劇情，在拯救「阿斯特爾提亞（Astoltia）」五大洲後，全新篇章將舞台轉向神秘的新大陸——「蓋蘭德地區（Landon）」。傳說中，沉睡於古代的勇者即將甦醒，而黑暗勢力也蠢蠢欲動。玩家受命前往調查這片被遺忘的土地，展開與「指引的盟友」們之間的邂逅與冒險，並逐步揭露過去封印勇者的真相。新劇情的鋪陳更加深沉，融合命運與宿命的糾葛，角色之間的情感描寫也更為細膩，引發玩家強烈的代入感。

操作與系統設計方面，仍以《勇者鬥惡龍X》的即時指令戰鬥系統為基礎，可選擇職業、組建隊伍並進行戰鬥。此資料片加入新職業如「魔物大師（Monster Master）」，拓展戰術選擇與職業配搭的多樣性。同時也擴展技能樹系統，讓角色培育更具深度。此外，還新增夥伴NPC「盟友角色系統」，允許玩家與故事角色共同戰鬥，提升單人遊玩時的沉浸與策略性。釣魚、道具合成、房屋裝飾等生活技能系統也有所擴充，讓非戰鬥內容同樣具有豐富性。

由於是線上遊戲，持續透過版本更新推出新內容，而作為2.0版本的重要擴展，無論在內容量還是品質上都獲得高度評價。玩家社群普遍認為劇情有著系列中少見的悲壯感與史詩氛圍，特別是與沉睡勇者相關的謎團與解答，帶來極具衝擊的情感波折。戰鬥與系統層面則被稱讚為比初期版本更為成熟、平衡，新增的盟友系統也改善了單人遊玩的體驗，對非硬核玩家更具吸引力。

在市場與媒體評價方面，於日本本土獲得極高評價。《Fami通》給予34/40的高分，特別肯定其劇情完成度與持續優化的遊戲系統。雖然主要針對日本市場推出，未有國際化計畫，但在日本RPG與MMO玩家間形成穩定社群，許多長期玩家認為這部資料片象徵《勇者鬥惡龍X》進入黃金時代，其深度與娛樂性遠超一般線上遊戲，亦保有系列招牌的故事魅力與角色魅力。

總結來說，《勇者鬥惡龍10 沉睡的勇者與指引的盟友 Online》是在原作基礎上全面進化的資料片。不僅強化世界觀建構與劇情推進，也讓職業系統與戰鬥設計更具深度，同時照顧到喜歡單人遊玩的玩家需求。這不只是MMORPG的一次擴展，更像是新章節的開始，為整個《勇者鬥惡龍X》宇宙添上濃墨重彩的一筆，對系列粉絲與日式MMO愛好者而言，無疑是值得體驗的奇幻旅程。

Dragon Quest X: The Sleeping Hero and the Guiding Allies Online (Japanese title: ドラゴンクエストX 眠れる勇者と導きの盟友 オンライン) is the second major expansion for the online RPG Dragon Quest X, developed and published by Square Enix. Released in Japan in December 2013 for the Wii, Wii U, and Windows platforms, this expansion continues the world established in the base game while introducing new story chapters, maps, character classes, and gameplay features that significantly enrich and evolve the overall experience.

The story picks up after the player has saved the five continents of Astoltia. In this new chapter, the stage shifts to a mysterious new continent known as the Landon region. According to legend, an ancient sleeping hero is about to awaken, while dark forces begin to stir in the shadows. The player is tasked with investigating this forgotten land, leading to fateful encounters with the "Guiding Allies" and a gradually unfolding truth behind the long-sealed hero. The narrative is more profound and emotionally charged than before, intertwining themes of fate and destiny. Relationships between characters are portrayed with greater nuance, enhancing immersion and emotional engagement for players.

Gameplay-wise, the expansion retains Dragon Quest X's real-time command-based combat system, where players choose a job class, form parties, and engage in strategic battles. This expansion introduces new jobs such as the "Monster Master," increasing the diversity of tactical choices and class combinations. The skill tree system has also been expanded, allowing for deeper character progression. A new feature, the “Ally Character System,” enables players to fight alongside story-based NPCs, improving the solo play experience and adding new layers of strategy and immersion. Non-combat systems like fishing, item synthesis, and home decoration have also been expanded, providing a richer and more varied lifestyle component to the game.

As an online title, the game receives regular content updates, and Version 2.0 is considered a major milestone both in content volume and quality. Players widely praised the expansion's emotionally resonant story, which many described as one of the most dramatic and epic arcs in the Dragon Quest series. The mysteries surrounding the sleeping hero and their resolution deliver powerful emotional twists. On the gameplay front, combat and system design were seen as more polished and balanced than the initial release. The introduction of the ally system greatly enhanced the solo play experience, making the game more appealing to casual and non-hardcore players.

In terms of market and media reception, the expansion received high praise in Japan. Famitsu awarded it a strong 34 out of 40, commending the well-crafted storyline and the continued refinement of its gameplay systems. Although the game was primarily aimed at the Japanese market and never officially localized for international audiences, it fostered a loyal community among Japanese RPG and MMO fans. Many long-time players view this expansion as a turning point that ushered Dragon Quest X into a "golden era," with a level of depth and entertainment that surpasses typical online RPGs, all while preserving the franchise’s trademark narrative and character appeal.

In summary, Dragon Quest X: The Sleeping Hero and the Guiding Allies Online is a comprehensive evolution of the original game. It not only expands the lore and advances the main story but also deepens the job and combat systems while thoughtfully enhancing the solo play experience. More than just an MMORPG expansion, it serves as the beginning of a powerful new chapter in the Dragon Quest X universe. For series fans and enthusiasts of story-driven Japanese MMOs, it is undoubtedly a fantasy adventure worth experiencing.