Someone explain the pun?

^ saitou_dousan was known as Serpent of Mino (美濃の蝮 Mino no Mamushi) . or in the anime, his title was the Viper of Mino. this year (2013) is the year of the black water snake.

ghostrigger said:
^ saitou_dousan was known as Serpent of Mino (美濃の蝮 Mino no Mamushi) . or in the anime, his title was the Viper of Mino. this year (2013) is the year of the black water snake.

Crap. Forgot about his nickname.