Mamoru Todou (藤堂 護, Tōdō Mamoru) is a fictional character and the Student President of Reihou Academy in the Kunio-kun series. He first appears in Downtown Nekketsu Kōshinkyoku: Soreyuke Daiundōkai, where he shows up during the opening intro. He is known for his huge dislike for Kunio and makes attempts to humiliate him in Downtown Nekketsu Kōshinkyoku, and Bikkuri Nekketsu Shin Kiroku.
Mamoru is a smug character who uses underhanded tactics and his wealth to get what he wants. Whenever his team loses in a sporting event to Kunio, he tends to react poorly as shown in Bikkuri Nekketsu Shin Kiroku. In fact, he goes out of his way to humiliate Kunio to the point of hiring people to do his dirty work and tell them lies, only for his attempts to end in failure. According to the English ending, it is said that his obsession with bring Kunio down is the cause of his strained relationship with his father Kounosuke Todou.
- In Crash 'n the Boys: Street Challenge, Mamoru was name Todd (a.k.a Theodore Thornley IV), a captain of the Team Washington High School, replacing Riki as a playable character.
- In River City Ransom EX, Mamoru is known as Titus.