It's hard to say exactly what Bela looks like, given that she's almost never seen without her armour. She wears a purple breastplate that leaves her thin, dark arms exposed, and a pair of heavy gauntlets that she uses as a medium for her psychic blades. Her face is concealed by a helmet with no visible eyeholes, marked with a number of distinctive circular patterns.
As it turns out, the School's experiments into Aura Drain weren't a total dead end. Bela is the product of those experiments - a psychic who uses Aura Drain to extract vitality, memories and other vital information from the School's enemies. Like many other Schoolkids, Bela herself is a stern, serious young girl who rarely speaks unless spoken to.
The Counselor and Ferrum are Bela's two primary handlers. She also spends a not-insignificant amount of time with Neodymium, often trying to bully and extort the other girl - but she's not very good at it, and so the relationship between the two is more akin to the kind of friendship you would expect from two emotionally-stunted young teens.