弁庆的母亲怀孕三年才生下他，生出来时已经有两三岁小孩的大小，发长及肩，牙齿齐全。据说他立刻大笑，并惊叹着外面世界的明亮，故乡纪伊当地人都称他为「鬼若」。他被遗弃在山腰上，被京都的大纳言收养，直到七岁离开成为一名僧侣。由于他的暴力行为，他被赶出了寺院，在日本游荡寻找自己的使命，然而也时常陷入麻烦。在意外导致一座寺庙烧毁后，他决定开始一项任务，在战斗中击败 1,000 名可恨的平家武士，并将他们的武士刀捐赠给一座寺庙。获得前 999 把刀很容易，但最后一把刀属于义经，这位武士把他高超的战斗技巧隐藏于他年轻的外表之下。

After being carried in his mother’s womb for three years, Benkei is born with long hair and teeth and the body of a small child. It is said that he immediately laughed and commented on the brightness of the outside world, leading local people in his native Kii (modern Wakayama) to proclaim that he is a devil. Abandoned on a mountainside, he is adopted by Dainagon, a Kyoto resident who rears him until age seven when he leaves to become a monk. Thrown out of the monastery for his violent behavior, Benkei wanders Japan in search of enlightenment, though only trouble seems to find him. After accidentally causing a temple to burn down, he decides to begin a quest to defeat 1,000 of the hated Heike samurai in battle and donate their swords to a temple. Obtaining the first 999 swords proves relatively easy but the final weapon belongs to Yoshitsune, a young boy whose appearance belies his great skill as a warrior.