why sin have black colored lighting? and is hes "summon humming bird" skill is one of hes powers or part of the control unit ya know for the game mechahinc sake
Mobile Minions are assumed to be Servants of the Master that are generated from the Master Ghost. Unlike normal servants however, they require Tension instead of Mana (Houriki) to summon, therefore they deplete part of the Master's stamina to a degree, that is all I can say for certain.
Sin's Humming Sword is his own personal servant, the other servants he can summon are Illyrian Army Knights. Sin hasn't fully adjusted to his abilities in terms of being able to use summon magic like Sol, Ky, Izuna, or Dr. Paradigm are (though the latter 3 are assisted by allies rather than just magic).
In addition to this, Sin has a seal placed over his eye due to his nature as a Gear. Most likely he inherited his father's elemental affiliation to Lightning, however most likely the reason the lightning itself is black (or more precisely, RED)... Has to do with either his inability to control and diffuse the energy properly, or it might be a result of his being a Half-Gear.
Regardless of the reason, there is no official explanation, so therefore it is most likely a style choice, related to his personality and character setting.