The Legend of the Eight-legged Serpent and the Nine-tailed Fox Demon

In fact, there is no connection between the serpent and Kyubi no Youko Fox! Just connected in Naruto.

According to the legend of Hachi Serpent, Hachi Serpent has eight heads and a tail, its eyes are as bright as "Phragmites communis", its back is covered with moss and trees, its abdomen is festering with blood, and there are often rain clouds (clouds in the sky) floating overhead. Its body is as huge as nine peaks and nine valleys, and it likes drinking very much. It is considered as a symbol of water disaster. Later killed by SUSANOO

The Kyubi no Youko Fox originated in China and finally arrived in Japan. It is one of the most famous ancient monsters. And one of the most famous legends is the story of Tamamo no Mae.

In Naruto, in the battle between Kyubi no Youko and Hachi, although Hachi and Kyubi no Youko were almost the same in strength, in the long-term battle of more than 1 years, Hachi's chakra failed to catch up and was defeated by Kyubi no Youko.