WWI munitions

Vancha and Wester were equally horrified by this new war of trenches,
machine guns, poison gas and tanks. They had seen mankind at what they’d
thought was its worst. As Cubs, Wester and Larten had feasted in war zones
and merrily watched soldiers killing each other. Vampires were coarse
creatures, lovers of battle, connoisseurs of combat. But there was no
pleasure to be wrung from this wretched, pointless butchery. No young
vampires cheered on these warring sides or gambled on their fortunes.
There was nothing noble or exciting about this massacre. It was simply a
sickening waste of life.

Progress across the war zone was difficult. Vampires were tougher than
humans, but they could be killed the same way — they weren’t immune to
bullets, bombs or gas.

***

The Saga of Larten Crepsley: Palace of the Damned, Chapter 16