Dynasty Warriors 9[a] is a 2018 hack and slash video game developed by Omega Force and published by Koei Tecmo.

[11] Dynasty Warriors 9 is an open-world hack-and-slash game played from a third-person perspective with stealth elements.

Certain items have different effects; for example, placing a gong in the house and interacting with it will allow the player to change the background music.

[15] The game also includes fishing, collecting resources to upgrade weapons and characters, camping, and other recreational events as well.

All characters share a common pool of acquired weapons, items, and map knowledge, but must be leveled separately.

In an interview with Famitsu in May 2016, Omega Force brand manager Kenichi Ogasawara commented that "the evolution from Dynasty Warriors 7 to 8 was insufficient", and hoped that the announcement of their next game in the series would "have a great impact".

[19] For the first time in the series, Dynasty Warriors 9 featured an open world environment, allowing players to enter and exit towns and freely explore the map of mainland China with considerable differences in elevation.

[13] The combat system, which in previous games relied on players linking together combos by pressing two alternate buttons designated to light and heavy attacks, was overhauled.

[10] The game's localization was handled by VOXX Studios rather than VoiceGroup, with all returning characters being voiced by different English-speaking actors, albeit now being credited for the first time in the series.

[33] GameSpot praised the game for its empowering melee combat, epic story, peaceful open world, and character designs, while lamenting the presence of several graphical and technical issues, lack of combat depth, and the need to repeat missions when swapping characters.

[38] Koei Tecmo announced an expansion titled Dynasty Warriors 9: Empires on September 27, 2020.

Like previous Empires expansions, it is focused more on strategy than the typical hack and slash, with the goal of uniting China under one banner through diplomacy and siege battles.

An early 2021 release window was originally planned, but Koei Tecmo later announced a delay to December 2021 for Japan and February 2022 in the West.