Calabim don't have Arquebuses (or cannons IIRC) 
however, I suppose with proper planning and Vampire use its not too necessary ... and by that I mean acquiring at least 7 death mana to have strength 10 spectre summons. And if those spectres are summoned by a combat 5 vampire then they are more like 15 power spectres.
In which case, their vampires are not only a useful unit in melee (if overly expensive Initially) but can also summon temporary mithril champions which cause no War Weariness if enough mana is accumulated.

however, I suppose with proper planning and Vampire use its not too necessary ... and by that I mean acquiring at least 7 death mana to have strength 10 spectre summons. And if those spectres are summoned by a combat 5 vampire then they are more like 15 power spectres.
In which case, their vampires are not only a useful unit in melee (if overly expensive Initially) but can also summon temporary mithril champions which cause no War Weariness if enough mana is accumulated.