[Imp]

Okay the first tank designed that came to fruition with the role of tank killing in mind, & yes breakthrough as in blitzkrieg. Other German tanks were like all designs then infantry support based.
Many people state it was designed as a tank killer in response to the T-34 & that is indeed wrong because it was conceived before the start of the war, the Panther was born from the T-34.
Char B1bis & KV were infantry support tanks / breakthrough tanks with slightly improved guns to help deal with armour. Char B after all carried as its main gun what was basically a howitzer not a high velocity tank gun, it didn't even have an APC round to start with because its an infantry support tank. Both it & the KV were I think designed originally to take out heavy targets like bunkers