Lets start off with the explantion of the Crusniks. This is not my materail.

Crusniks are vampires who feed on the blood of other vampires.They possess immense power and destructive potential and are nearly invincible.Where as the Methuselahs are either born or infected, the Crusniks are unique beings created as a result of an experiment during the Mars Colonization Project. The four Crusniks, Cain, Seth, Abel, and Lilith, were test tube babies created for the Mars Colonization Project by the UNASF with genetically enhanced bodies. They were infused with the Crusnik nanomachines that were found on Mars as their enhanced bodies were the only ones capable of surviving the procedure. The exact circumstances behind the infusions of Seth, Abel, and Lilith are unknown, while Cain's infusion was done by Seth to save his life after a fatal accident.
Crusniks possess unique attributes that separate them from Methuselahs. For instance, both Abel and Cain sport angelic wings and can fly quite easily. Crusniks can transmute their blood into weapons and often possess psychokinetic powers. Abel can generate powerful bio-electric fields while Cain can use psychokinetic waves to pulverize objects and enemies and to generate barriers. Seth can reduce people and objects to dust using sound waves.
In order to activate his Crusnik powers, Abel usually issues a verbal or mental command to the nanomachines in his body. "Nanomachines: Crusnik 02 - __% Activate" while in the manga he silently activates Crusnik mode and receives a confirmation from the nanomachines of "Crusnik 02 Loading. Limitation at __%... Acknowledged". In the anime, neither Cain nor Seth demonstrated a need to do this in order to activate their powers, and there are several times when Abel activates his powers without saying his usual command.