Wonder Boy in Monster World, aka in Japan as Wonder Boy V: Monster World III (ワンダーボーイV モンスターワールドIII)
0Wonder Boy in Monster World, known in Japan as Wonder Boy V: Monster World III, is a side-scrolling action role-playing game originally developed by Westone and published by Sega for the Mega Drive/Genesis in 1991. It is the fifth game in the Wonder Boy series and the third game in the Monster World sub-series, following Wonder Boy in Monster Land (Super Wonder Boy: Monster World on the Japanese Sega Mark III) and Wonder Boy III: The Dragon's Trap (Monster World II: Dragon no Wana on the Japanese Game Gear).
Versions for other platforms were also made. In 1993, Sega released a Master System version of the game specifically for the European market, while in 1994, Hudson Soft remade the game for the TurboDuo under the title of The Dynastic Hero (超英雄伝説ダイナスティックヒーロー, Chō Eiyū Densetsu Dainasutikku Hīrō), featuring an all-new theme and cast of characters. In 2007, the Turbo Duo and Mega Drive versions were re-released on the Wii Virtual Console download service.
In the Genesis and Master System versions, Monster World is described as a once peaceful land. One day, peace was shattered by an invading army of monsters, with seemingly no source for their appearance. The Fairy Queen Eleanora headed to the town of Purapril to seek aide from the Princess after her town of Alsedo was attacked, only to discover that the Princess went missing and many other towns across Monster World have been attacked as well. Eleanora offers up a prayer to the gods that someone, perhaps even a hero, would step forward. Her prayers reach a young man named Shion, who vows to defeat the invading monsters and make Monster World peaceful again.
In the Turbografx-16 release, The Dynastic Hero, Monster World is instead named as the land of Tarron, a woodland that was once known as "the peaceful paradise". One day, the evil Drillkor Empire of reptilian monsters attacked Tarron using their advanced technology and space station. Rippen the Beast, Emperor of the Drillko, attacks Tarron Castle and imprisons the Princess in her own castle dungeon. The princess prays to the gods of Tarron for the aide of a hero. The call to adventure is answered by a young warrior named Dyna, setting out to the fairy village Lindor for information from Queen Nora.
『ワンダーボーイV モンスターワールドIII』 (WONDERBOY V Monster World III) は、1991年10月25日に日本セガから発売されたメガドライブ用アクションロールプレイングゲーム。
同社の『モンスターワールドシリーズ』の第3作目。勇者の子孫である主人公の「シオン」を操作し、モンスターワールドを救出することを目的としている。『スーパーワンダーボーイ モンスターワールド』（1988年）より後の世界を舞台としており、過去作の登場人物の子孫やモンスターが再登場する。主人公は剣のほかにマジックアイテムを用いて魔法が使用できる。
開発はウエストンが行い、ディレクターは後にエニックスのスーパーファミコン用ソフト『ダークハーフ』（1996年）を手掛けた平田豊およびセガサターン用ソフト『闘神伝S』（1995年）を手掛けた清水芳久が担当しているほか、前作『モンスターワールドII ドラゴンの罠』（1989年）から引き継いだスタッフとしてプログラムは栗原孝典、音楽は坂本慎一が担当している。
1994年には続編に当たるメガドライブ用ソフト『モンスターワールドIV』が発売された。