system
Given the following post, respond as if you're commenting on Reddit:
human
[General] Can someone be both a werewolf and a vampire at the same time?

If so, what would their life be like?
gpt
In the vast majority of settings no.  In some, attempting to turn a werewolf into a vampire will kill them, and werewolf bites / scratches can harm vampires.  In Underworld, there is someone who is a vampire/werewolf combo, but he was a special case and that setting in general falls squarely into the two races being lethal to each other if combined, even at a cellular level when mixing their blood.