|English Translation||Drill Tooth (Old Norse)|
|Shikai Abilities||Zanpakutō spiritual harmonization|
Ratatosk (ラタトスク, Ratatosuku), also referred to as Ratatosk's Chain (ラタトスクの鎖; Ratatosuku no kusari), is the third zanpakutō of the Two Legendary Zanpakutō, and is the zanpakutō that would allow its sister blades, Vedrfolnir and Nidhogg, to combine their abilities and achieve a state of power unrivaled in written history. However, its existence remains highly unknown; the only way to recognize that such an item actually exists would be to utilize knowledge of shinigami lore.
Yamamoto ordered Ratatosk to be forgotten in written history in order to prevent it from falling into the wrong hands and used in conjunction with Nidhogg and Vedrfolnir to achieve enormous powers.
Powers and abilities
The best known power is its ability to harmonize the spirits of Nidhogg and Vedrfolnir in order to gain access to the great dimensional power, as well as use Nidhogg's and Vedrfolnir's powers in conjunction with each other.
Besides this, Ratatosk's abilities involve time and space, referred to by its spirit as Void. The chain zanpakutō can become tangible or intangible at the whim of its wielder, making parrying moves against the zanpakutō unreliable as well as maximizing the efficiency of chain wielding.
Behind the scenes
Ratatosk originates from Norse mythology whereas it is a squirrel that sends messages back and forth between an unnamed eagle at the top of the Yggdrasil Tree and Nidhogg beneath it.