The KV-2 is a tier 3 heavy tank. Iosif Stalin's pussy destroyer.
Historical Use: The KV-2 was intended as an assault tank. it was meant to destroy bunkers and support the infantry (like the early panzer 4s) rather than fight other tanks. It was horribly designed, with the turret only being able to do a 360 degree rotation on completely level ground. The 152mm howitzer was devastating to targets, including tanks, but the KV-2s slow speed, high silhouette, and poor reliability made fighting tanks difficult at best. The KV-2 was only produced in small numbers, and when the German Army took the factory it was made it, it was never restarted elsewhere, or when the factory was re-taken by the Red Army.
Ingame Use: The KV-2 is slow, not that well armoured, and highly visible. The 152mm howitzer has a massive about of firepower, but also has a massive reload time.