Efriend is a side character and secondary antagonist in the Red Bat. He is Niflheim's former boss and a mix of a variety of different species, from werewolf to vampire to fairy and everything in between.
Efriend initially claimed to be the leader of an independent organization as well as The Rival who had the same intentions as Gabriel; to end the fighting between the Vanarchist and BBP. However, in reality, he was simply a high ranking member of the Vanarchists whose sole intention was to kill Gabriel. However, Gabriel saw through his lies, and Efriend was shot by an experimental bullet to make him reveal the Vanarchist's plans. Despite this, he escaped alive.
A while later, Efriend arose once again and actually allied with Arborius (or rather became his and the rest of the villains' master) in an attempt to take over the world, helping develop a wolf serum that even caused Gabriel to hallucinate. However, Gabriel managed to kill him before his plan was enacted.
Efriend comes off as a very myserious figure with a knack for sarcasm who initially seems to have a strong sense for justice. However, as it would turn out, Efriend is nothing more than an egoist who seeks world domination. He is still minorly humorous, but in a more satanic sense.
Although he is not shown fighting often, it is strongly implied that Efriend is an expert with knives. In addition, although he is never portrayed using such powers, he does possess the abilities of werewolves, vampires, fairies, etc. due to his DNA.
As evidenced by his work with inventing a new wolf serum and the numerous potions he carried, Efriend was potentially a very intelligent scientist or chemist of some sort.