Hiro Kasai is a character in killer7. He is a member of the Liberal Party in Japan. He works to negotiate between his party and the US. In Sunset, he sends Garcian Smith to the KAKU building to assassinate Jean DePaul. He makes another short appearance in Smile much later in the game, falling from a rooftop in bondage gear, seemingly forced to by Kenjiro Matsuoka. That is where he meets his demise. Because he was not clearly identified as Kasai in this scene, some fans mistakenly believed him to be Iwazaru due to the bondage gear.
According to Hand in killer7, in 1967, Kasai met with Harman Smith in Hakone, Japan and gave the Smiths a mission involving investigating the security of the votes of countries involved with the Asian Security Treaty. However, it is extremely unlikely that this information is accurate as Kasai would have been nine years old at the time.