Final answer:
In the anime adaptations of Gintama and SKET Dance, the characters Gintoki Sakata and Switch Kazuyoshi Usui are voiced by the same seiyu, Tomokazu Sugita.
Step-by-step explanation:
In the anime adaptations of Gintama and SKET Dance, the two characters with the same seiyu (voice actor) are Gintoki Sakata and Switch Kazuyoshi Usui, respectively. Both characters are voiced by Tomokazu Sugita. Gintoki Sakata is the main protagonist in Gintama, known for his lazy and comical personality, while Switch Kazuyoshi Usui is one of the main characters in SKET Dance, known for his stoic and intelligent demeanor.