Thunderbolt allows Amaterasu and Chibiterasu to summon bolts of lightning without needing a source. The size and damage of the thunderbolt depends on the size of the drawing.
To use Thunderbolt, draw a lightning bolt (ϟ). For best results, the lightning bolt drawn should be sharp and jagged, with the end of the bolt on the desired target. Depends on size of the drawing, 3,6 or 9 Ink Pots may be consumed.
After restoring Shinshu Field's Guardian Sapling, Amaterasu found Ida, who has been pinned down by a small curse. She gave him a Traveler's Charm, and the curse was be lifted. In her later returns to Shinshu Field, Ida was found running around the area, and was challenged to a race, which consist of Amaterasu chasing down Ida and tackling him. After his first defeat, Ida started leaving spiked balls on his trail, which could severely hinder Amaterasu's speed, but despite these obstacles, the sun goddess prevailed. Since then, Ida rejected attempts to race with him until after Ninetails' defeat, which then he participated in a race for his pride, putting his Gimmick Gear as a stake, which Amaterasu obtained after her victory. Subsequently, she delivered the item to Gen at the Aristocratic Quarter of Sei'an City per the old inventor's request to complete his creation of a lifetime. As the invention came to life, Amaterasu found Gekigami, his power restored from Gen's zeal, and granted the sun goddess his power.
Thunderbolt is purchased for ¥50,000 at the shaman in Yakushi Village after 9 people have moved in.
Spoilers end here.
When Thunderbolt is used, the kanji 迅 (jin, swift) appears.