NessMitsurugi no Mikoto, Saji
Full art:
Appearance:
Left: "Shell-shaped shoulder armor"
Right: "Reptile legs"
Snake: "The snake on its tail in dragon-mode moves to its left arm while in human-mode (can move across all of its body)
During a slashing attack, it can move to the sword and jump out"
Futsu no Mitama no Mitsurugi
Full art: "The tip of the tail has been possessed by the flame snake"
Source.
Full art:
Appearance:
Left: "Shell-shaped shoulder armor"
Right: "Reptile legs"
Snake: "The snake on its tail in dragon-mode moves to its left arm while in human-mode (can move across all of its body)
During a slashing attack, it can move to the sword and jump out"
Futsu no Mitama no Mitsurugi
Full art: "The tip of the tail has been possessed by the flame snake"
Source.