Since Raith and Balam started this fight, has Balam not been injured in his hand?
When he was a colossal creature, Raith pretty much damaged his entire hand with Bal's lightning. Yet the demon was devastated that a human cut through his skin.
This was because Balam in this form had extraordinarily tough skin, a skin that never should be penetrable. It didn't matter the sword used, Balam was part of the few demons who had the [origin].
The [origin] bestowed upon these demons an extraordinary augmentation of their physical abilities, rendering them impervious to divine powers or any form of magic designed to negate their inherent nature. Remarkably, the [origin] was primarily found in archdemons, making Balam and a handful of other greater demons who possessed it truly exceptional.