在4本体的事件之后的某一天，从幸福制药公司的地下洞穴中突然出现大量怪物。兰斯在该公司的社长的请求下，接受了清除工厂周围出现的魔物的任务。由于希露在家工作无法离开，兰斯带着雅典娜2号前往消灭怪物。

This game is not considered part of the official Rance universe timeline, forking off after the events of Rance 4.2, as a "What if" episode. However, many characters and ideas featured in later Rance games originated in Kichikuou Rance. The game begins at the start of LP0003. The warrior Rance, accompanied as always by his faithful slave Sill Plain, has been living as the leader of a group of bandits in northern Helman after killing their previous leader as part of a job given to him by the Keith Guild. While Rance greatly enjoys the raping and pillaging that comes with being a bandit leader, the guilt-ridden Sill believes that he is in danger of losing what remains of his conscience and genuinely becoming a villain. After attacking the city of Golak, Rance's group alerts the attention of Ruberan Tser, commander of the Helman volunteer army, who launches a counterstrike on them during their second attempt at pillaging the city. Unable to fight against a genuine army, the bandits are quickly destroyed, Sill is captured by the Helman Army and Rance is forced to flee for his life. Rance evades the Helman army for several days, with both his equipment and health steadily declining all the while, before he finally passes out from fatigue along the Leazas/Helman border. He is found on the verge of death by Kentou Kanami, the personal ninja of Leazas' queen and Rance's longtime admirer Lia Parapara Leazas, who brings him to Leazas castle. After three days of recovery, Rance finally regains consciousness and, completely humiliated by his defeat at Helman's hands and desperate to rescue Sill, demands that Lia give him the Leazas Army to destroy the enemy nation. Finally seeing an opportunity to have Rance to herself, Lia agrees on the condition that he first marry her, which Rance reluctantly accepts. As the new king of Leazas, Rance sets his first steps on a path that will lead to either world domination or death. [Taken from the [url=https://web.archive.org/web/20230118041246/https://alicesoft.fandom.com/wiki/Kichikuou_Rance]AliceSoft Wikia[/url]]

あらすじ ランスとシィルが入り込んだのは最後の一人が脱出不能という「玄武城」。そこにはリズナという女の子が閉じこめられていた。 システム 移動・戦闘など、すべての行動に乱数的要素を用いた変り種のゲームになっており、章ごとの制限時間を使い切らないよう各種行動をしていく。アイテム入手は装備を含めてほとんどドロップに頼らなければならず、持てる数も20個程度となっており取捨選択も必要。このため運に左右される部分が大きいが、サイコロやルーレットの出目をある程度操る事も可能。女の子モンスターを捕まえてパーティに組み込む事も出来る。