The KV-1 (Klim Voroshilov) is famous Soviet heavy tank from the Great Patriotic War, known as one of the best-protected tanks from the early years of World War II. Development of the single-turreted, anti-tank gun-protected tank began in 1938–1939 under the direction of a team of designers led first by A. S. Ermolaev and then by N. L. Dukhov. Production began in 1940 with early vehicles armed with a 76mm L-11 cannon. Production of the KV-1 (L-11) continued from February 1940 until early 1941, with a total of 144 vehicles built. The KV-1 (L-11) saw extensive service during the Winter War and the Great Patriotic War, proving highly effective and halting the advance of numerous German formations in several sectors.

The KV-1 (L-11) was introduced during the closed beta testing for Ground Forces before Update 1.41. Its well-protected, all-around armor makes the tank highly resistant to most opponents' guns, especially when angling the hull. Its BR-350A APCBC shells have modest penetration, but their explosive filler provides considerable post-penetration damage. However, the cannon's reload time is rather long, and the slow turret traverse makes close-range engagements difficult. The KV-1's mobility is also mediocre.