I'm starting to see a common misconception about how much damage a borg can actually withstand so I'm just going to link to the rule/system section responsible and lay out a quote from it;
https://magiworld.forumotion.com/t2457-specialization-system#11679
https://magiworld.forumotion.com/t2457-specialization-system#11679
Specialization System wrote:D-Tier: Can have one basic staffs C-Tier and below spells with a single element can be used. Borg can defend against a single D-Tier ability before breaking.
C-Tier: Can have one basic staff. B-Tier and below spells with a single element can be used. Borg can defend against 1 C-Tier, or 2 D-Tier abilities before breaking.
B-Tier: Can have one basic staff. A-Tier spells and below can be used. At this tier, a Magician can learn a second magic type. Both types can be used in conjunction to create brand new techniques and magics. Borg can defend against 1 B-Tier, 2 C-Tier, or 4 D-Tier abilities before breaking.
A-Tier: Can have up to three advanced staffs with special abilities [see weapon guidelines - only 1 may be taken into a thread at a time]. A-Tier spells and below can be used. Borg can defend against 1 A-Tier, 2 B-Tier, 4 C-Tier, or 8 D-Tier abilities before breaking.
Ω-Tier: Can have up to three advanced staffs with special abilities [see weapon guidelines - only 1 may be taken into a thread at a time]. Ω-Tier spells and below can be used. At this tier a magician can learn a third magic type anywhere on the wheel. All three types can be used in conjunction to create brand new techniques and magics. Borg can defend against 1 A-Tier, 2 B-Tier, 4 C-Tier, or 8 D-Tier abilities before breaking.