We know dervish can use Gods form and power.
When we fight Warden Amala , during Meta fight and story, she channelize Balthazar Form even if this one is dead.
Looking better this form is more darker than the classical one.
Is It possible the war between brothers in FoW was ended with Menzies's victory?
This will explain 'cause the gods are always named "The six" while Balthazar was stripped down the title without any canonical war between gods, the quote about war, and his hunger about gain power back even if all Tyria will be destroyed.
This will explain also "Lyssa gave his mirror to Balthazar" theory, to hide Menzies her help, not to whole panthon.