The new weaponry that I think was the most feared by combatants was the tank. The tank was first used in World War I and was an incredibly powerful and intimidating weapon. The tank was a heavily armored vehicle with a large gun mounted on the top, and it could move quickly across the battlefield.
The two main reasons why the tank was so feared by combatants were its sheer power and its mobility. The tank was much more powerful than any other weapon on the battlefield, and it could quickly move from one location to another, making it difficult for the enemy to predict where it would strike next. Additionally, the tank could take a lot of punishment, making it difficult for the enemy to destroy it. This made it an incredibly intimidating weapon for the enemy to face.
Overall, the tank was the most feared new weaponry by combatants due to its immense power and mobility.