Heavy tank
The Char 2C was one of the largest tanks ever produced. At the start of World War II, France and the Soviet Union were the only countries to have inventories of heavy tanks, such as the Char B1, T-35, and KV-1. The Matilda II was designed under the British infantry tank concept which is similar to the heavy tank having thick armor and weighing more than their other tanks. It’s usually separate because they have less firepower with their cruiser tanks (comparable to mediums) at the time having the same main armament but more machine guns. Later war examples were the German Tiger I and II, as well as the Soviet IS series. Note that "heavy" versus "medium" is more a question of tactical roles than weight; the Panther, for example, was a "medium" tank that outweighed most Allied "heavy" tanks.
German tanks in World War II
The Panther was a medium tank (45 tonnes) with a crew of five, which was designed to counter the Soviet T-34 tank. In weight it was comparable to Soviet heavy tanks. This tank was introduced in the Battle of Kursk, the largest tank battle in history. It had sloped armor which increased the effective thickness of the armor from to roughly , effectively making the front of the tank virtually impervious to enemy fire. However the sides of this tank were very vulnerable, ranging from only to of either barely sloped or completely flat armor plating. The tank carried a high-velocity 75 mm gun, which possessed more penetration than the Tiger's 88 mm gun at short range. Series production began in 1943. The tank was plagued with mechanical problems throughout its service life, several of which were never quite fixed, even after the war. Despite this, the tank is considered by some to have been the best tank in the war, and to have greatly influenced post-war tank designs, setting a role model for the balance of firepower, mobility, and armor protection.