here's my story of a creature of Nahoian legend the former servant of king Takadox (idea by @AntrozT6)
Vamprah looked around and sighed. complete darkness all around him ,"again" he thought. it had been a year since the end of the Kahnoi war and for that length of time he had been wandering Managi alone. "darn it"he thought. he had missed the king and lamented Pelegia's death at the hands of the murderous Nahoians"and I can only imagine what they have done to Takadoxe's heir Kyrehx ."he grumbled as he grabbed his sack. he then noticed a light in a nearby cave he turned and entered the cave it was fairly large with a lava pool on one side. "nice shelter"he thought when suddenly a loud voice shook the cavern it said"what are you doing in Managi Nahoian." he turned around and saw what made the noise standing before him was a 15 foot tall demon. " I am a fugitive" he replied in a shaky voice "well then who are you" said the demon. " Vamprah who are you" Vamprah answered to which the demon said "I am Kulta the soul grinder." "oh gosh"Vamprah thought. Kulta then said "what is it you seek most matoran" Vamprah said "power" Kulta then turned and pulled something from the lava "I give you the Avsa" Vamprah readily took the mask and put it on. the next thing he knew he felt like he was burning on the inside and Kulta said"I fuse you with the mask of hunger and forever shall you hunger for the blood of Ekimu's children" with these words Vamprah watched in horror as he changed into a bat like beast and Kulta made a laugh that would haunt Vamprah for eternity when all went black except a sudden lust, a lust for blood.
hope you like it not 100% sure about his part in the story