If you just want to know what Zhu Xian means.
Then it can be directly translated as " To kill Xian"
诸 zhu means to kill, but it's not commen in everday conversation. Instead, 杀 sha, is what we usually use.
仙 xian , this is very hard to explain. In old chinese tales. Everything can become a Xian, in the way that they develop themselves both soul and body. It doesn't matter it's human-being, a fox, a snake, or just a pensil. Everything has its own soul... I myself find this explanation commic....
Anyway, it's not so import to know this Xian stuff....