All 3 major pet classes with a division of power (Beast, Mage, Necro) have access to the LDoN Calliav line up through Ward, Guard, and Protection.
Mages and Necros have access to one more than beasts called Bulwark of Calliav obtained through OoW/DoDh rune turn ins, NOT through LDoNs.
That said, the spells are purchased at different vendors for the different classes.
For instance, beastlords must rack up 410 pts in Miragul's Menagerieto buy Guard of Calliav from the EF camp merchant.
Mages must rack up 450 pts in the Mistmoore Catacombs to buy Guard of Calliav at the BB camp.
Necros must rack up 410 pts in the Takish-Hiz to buy Guard of Calliav in the NR camp.
You have to remember this, the spells are class and camp specific. Even if I had 1000 at the NR camp, I could NOT buy Guard of Calliav from the NR merchant b/c he sells the Necro version. To buy the beast version, I'd need 410 at the EF camp.
Here's a handy link for research what spell for what class at what camp: