Gallus can be very dangerous, as the tome he wields has the nasty ability to reduce a selected target's HP to 1. However, the odds of this taking place are relatively low, as the Hell spell is highly inaccurate. It is recommended to use characters such as Shanan with the Balmung or Julia with the Book of Naga to face off against Gallus.
Zehn, Gallus' Japanese name, is a German number, which, in this case, means 'ten'.
In the English version, the Deadlords' names are based off the Latin names of the animals of the Chinese Zodiac. "Gallus" means "rooster", the tenth animal of the Chinese Zodiac.