Onimusha Tactics is a strategy installment in the Onimusha series, released for the Game Boy Advance. It does not follow the storyline of the previous PlayStation 2 games, and is considered a side story. However, the game features a similar plot: a samurai who possesses the Oni Gauntlet can become an Onimusha and fight against Nobunaga and his army of Genma.
The samurai is Onimaru, who is supported with a wide range of characters, many of which are the same as their PlayStation 2 equivalent. However, there are some returning characters from other Onimusha games such as Magoichi, Ekei, Kotaro, and Mitsuhide Akechi. Onimaru battles the Genma, until the player ultimately reaches the notorious Nobunaga. New to the series are additional chosen warriors whom receive the power of the Phoenix, Tortoise, Tiger and Dragon to assist Onimaru. These animals correspond with the Chinese celestial animals that represent the cardinal directions. This reference was also a puzzle in Onimusha 2: Samurai's Destiny.
- Onimaru - The main protagonist. He was raised by Sandayu with his sister Oboro. Onimaru has inherited the Oni Gauntlet and is on a journey to defeat the genma that are led by Nobunaga Oda.
- Ageha - A female Genma descendant, she helps Onimaru and his friends while fighting the Genma.
- Oboro - Onimaru's sister. She joins the party after the beginning tutorial has been completed. Oboro has a cheerful personality, making funny remarks at most things said to Onimaru during his quest. Being Onimaru's sister means that she is also a descendent from the Oni Clan, and being trained, will turn one of the best healers at the game, with the Heal-all ability. Oboro's downside is her low HP, making her fragile to face tough Genma or bosses.
- Bomaru - Bomaru is the first spear-wielding warrior to join Onimaru's party. He has short hair and wears a blue hairband. He is a useful fighter, and learns healing at level 15. His most powerful skill is the Triple Stab, which can stab up to eight enemies in a row.
- Tsubame - Tsubame is a kunoichi, female ninja from the Iga, and the first of them to join Onimaru's party. She's very sincere and tends to say more than expected for a trained ninja. Being a ninja, Tsubame can move more spaces than most characters, but also has a low HP compared to others. She can strike enemies with thunder from far distance.
- Kabuki - Kabuki is, as the name implies, a kabuki-actor. He joins Onimura's party after receiving help to defeat some Genma, and becomes a loyal companion. He likes beautiful women, money and performing. He has good HP, and his Strongman mode ability is very useful during battles.
- Saizo - Saizo's a ninja from Iga, but deserted during his training and became sought after by the other Iga residents, with a reward for his head. Later, he sees the courage of Katsuhisa and Shikanosuke and feels ashamed of his attitude. He joins Onimaru's party to help other people and regain his honor. He also has the ability to steal from foes, but like any other ninja, doesn't have a high HP or high defense stats.
Onimusha Tactics is very similar to Final Fantasy Tactics Advance, also released for the Game Boy Advance. The player is presented with an 3/4 camera view of a detailed and grid-like battlefield. The point of the game is to defeat the opposing team of demon or opponents, and raise the player's character by experience points gained in battle. By defeating enemies, such statistics for a character include strength to dictate attack power, speed to decide turn order and others. The game allows the player to equip their warrior with various weaponry for different situations, such as katana, spears and other bladed tools.