The Akame ga Kill! manga and anime series features an extensive cast of fictional characters. The visuals of the characters were designed by Tetsuya Tashiro, while their stories were created by Takahiro. The story focuses on Tatsumi, a young warrior who joins an assassin group called Night Raid to fight corruption from the Empire. Its members, along with other characters in the series, wield super weapons called Teigu (帝具, Anime: Imperial Arms).[ch. 5]
In 2007, Takahiro was asked to do a manga for Square Enix magazine. He originally came up with the idea of an "all-female band of assassins, and the protagonist is a boy who is captured by them and has to work for them." After his editor approved the idea, he waited on serialization until his company had stabilized and had released two other titles, during which he developed the characters, story and world. In August 2009, following the release of Majikoi - Oh! Samurai Girls, Takahiro looked for an artist for the serialization, and recruited Tashiro Tetsuya to do the illustrations. He liked Tashiro's ability to draw fast-paced action scenes and that he can draw cute girls.[vol. 1:postscript]
Takahiro has written additional background information and profiles about some of the characters in the postscripts of the volume compilations, such as for the Three Beasts[vol. 3:postscript] and the Jaegers.[vol. 4:postscript] The Danger Beasts (危険種 kikenshu) were conceived to be any creature that attacks the humans in the world and are similar to monsters seen in role-playing games with different classifications from Class 4 to Class 1, and Special and Super Class designations at the top for the legendary beasts.[vol. 5:postscript]
The main characters are members of Night Raid, a team of assassins who help the Revolutionary Army's efforts to overthrow the corrupt prime minister and restore peace and order to the Empire.[vol. 1]
Tatsumi (タツミ) is a swordsman who sets out to the capital city to raise money for his impoverished village. He has brown hair and green eyes. Separated from his two companions, Tatsumi is swindled of his money, but is taken in by a girl with a wealthy upbringing.[ch. 1] When he tries to defend that girl from Night Raid, he soon discovers that the girl had actually tortured and killed his comrades, so he kills her and is recruited to join Night Raid,[ch. 1] He accepts, as their actions of fighting corruption would eventually help his village.[ch. 2] His primary weapon is a short sword, but he later inherits Bulat's Teigu "Demon Armor: Incursio" (悪鬼纏身 インクルシオ Akki Tenshin: Inkurushio), which was created from the still living flesh of an adaptive dragon Danger Beast called Tyrant. While normally a short sword, Incuriso can form armor around the user and grant them powers such as invisibility and superhuman strength.[ch. 5,14] However, Tatsumi's continued use of Incursio takes a toll on his body, and his body and his humanity are consumed by Tyrant. In the manga, he transforms into Tyrant but retains his mind,[ch. 76-77] but in the anime he dies after defeating Shikoutazer. In the manga, after the war, Tatsumi, trapped in his Tryrant form for life, returns to Mine's side, and they settle in his old village to raise the child they conceived before she fell into coma.[ch. 78]