Which thunder god is also a deity of swords in Shinto?

The Shinto thunder god who is also a deity of swords is Takemikazuchi.

Takemikazuchi is a powerful kami associated with thunder, swords, warfare, martial strength, and earthquakes. He is especially revered as the deity of Kashima Shrine in Ibaraki Prefecture, and Kashima shrines throughout Japan preserve his worship. In traditional iconography and later folklore, he is a divine warrior rather than merely a weather god.

According to the Kojiki, Takemikazuchi is born from blood that splashes from the sword of Izanagi after the creator god beheads the fire deity Kagu-tsuchi. This origin links him to both thunderous force and sacred weaponry. He later travels to Izumo to demand that Ōkuninushi surrender earthly rule to the heavenly gods.

Takemikazuchi also defeats Takeminakata in a famous contest of strength, often treated as the mythic precedent for sumo. During the Edo period, images of Kashima/Takemikazuchi show him subduing Namazu, the giant catfish believed to cause earthquakes. Susanoo and Futsunushi also have martial and sword associations, but Takemikazuchi is the direct answer to this thunder-and-sword description.