A Second serves a Dominion or Seraph as his trusted right hand and second-in-command (a Seraph's second has the rank of dominion), whose responsibility it is to see that her supervisor's orders are carried out.
In some sense, a second acts almost as a Templar, serving as bodyguard, aide and messenger ; also, a second is presumed to speak with her supervisor's authority. Her level of status relates directly to the status of the one she serves.
A second is a member of her dominion's Sabbat pack (if he has, one), and shares a Vinculum bond with him (and likely the pack as well). A dominion may take one second; any larger number must be approved by the Seraphim. A Seraph can have as many as three seconds (the number of the second Generation, the childer of Caine). The second can be a childe or a loyal packmate, but the duty cannot be imposed; it must be accepted freely.
A second is expected to be absolutely loyal, to give all of his energy and attention to his dominion's business and personal safety, and to be gladly willing to give his unlife for that of his dominion or Seraph.
This devotion far surpasses that engendered by a traditional blood bond. The basis of their extreme dedication lies in Eastern traditions of selfless service where a sultan might order one servant to jump from the top of a minaret and be obeyed, while another servant might take an arrow meant for his lord or even gladly drink poison, as the supreme demonstration of his devotion.
In displaying a similar degree of loyalty, a second also demonstrates the loyalty of a childe to his sire - or the loyalty the Antediluvians themselves should have shown their master, Caine. Thus does a second prove both the Worthiness of the one he serves, and his own, for the final night of `Caine's judgment on all his childer.
In the long, violent history of the Black Hand, two seconds are known to have committed themselves to the sun rather than face the shame of their failure to die in their dominion's defense.
A dominion whose second is slain in her defense must make answer to the Council of Seraphim as to the causes of that faithful servant's Final Death; only if she is cleared of blame is she permitted to take another.
A second who survives when his dominion has perished is likewise judged, and if found at fault, is executed as a traitor to his vow.