The Ki-45 Kai-Tei, otherwise designated as Type 2 Two-Seat Fighter, Improved Model D (Tei/丁) (二式複座戦闘機 丁型), was the last production variant of the Ki-45 series. Influenced by Navy J1Ns equipped with 20 mm cannons mounted at an oblique angle in the fuselage to shoot down bombers from below (Schräge Musik), the Army followed suit by experimenting on Ki-45 Kai-Hei models. They equipped two Ho-5 20 mm cannons while removing the belly-mounted 20 mm. Positive combat results with this configuration led to the streamlined production of the Ki-45 Kai-Tei, which also removed the rear gunner. Previous models of the Hei and Kō variants were retrofitted with the Tei armament by removing the belly-mounted 20 mm cannon.

It was introduced in Update 1.31. While the Ki-45 Kai-Tei historically removed the rear gunner, the model in War Thunder is actually a Ki-45 Kai-Hei (Tei-armament) that retains the gunner seat. The main feature of this aircraft is, unsurprisingly, the Schräge Musik cannons mounted in the centre of the fuselage. These cannons are not straightforward to use, as they require a keybind to switch to a different point of view to fire upward. It's best to fly at a lower altitude than the targeted bomber, matching its speed as closely as possible. This allows the guns to stay on target with minimal need for leading (although this can vary depending on speed and altitude), and destroy bombers with well-placed bursts from the safety of the gunner's angles. The Ki-45 Kai-Tei is also the only Ki-45 able to be equipped with ground ordnance, with two 250 kg bombs.