Ajin:Demi Human is a 2017 Japanese movie based on the manga of the same name.
Pistols
Colt 1911A1
The Colt M1911A1 can be seen used by the Sato (Go Ayano).
War time issued (WWII) Colt M1911A1 Pistol - .45 acp
The another shot of Sato's colt.
SIG-Sauer P226
Factory black (K-Kote) SIG-Sauer P226 pistol - 9x19mm. This is a real movie gun and has appeared in several motion pictures.
Unknown Pistols
Shotguns
Remington 870
Remington 870 Police Magnum with black synthetic furniture - 12 gauge
]
Submachine Guns
Heckler & Koch MP5A5
Heckler and Koch MP5A5 - 9x19mm.
Rifles / Carbines
M4 Carbine
Colt M4A1 SOPMOD with M68 Aimpoint reflex optic - 5.56x45mm
Others
Tranquilizer Pistol
Freezing Launcher
TAT(Counter-Ajin Special Operation-Forces) uses a Freezing Launcher