This New Band of the Hawk is a mercenary group of abominable creatures known as Apostles founded by the "White Hawk" Griffith after The First Hawks were nearly wiped out, with the exceptions of Guts, Casca, Rickert, and Griffith. During the Eclipse, when Griffith sacrificed them to become Femto, the fifth God Hand.
For the original and heroic Band of The Hawk go Here.
With Griffith's resurrection into the human world via Incarnation Ceremony, Griffith started to form a new Band of the Hawk combining human soldiers with Apostle, including Nosferatu Zodd, Locus, Irvine, and Grunbeld. The new Band of the Hawk is much greater in number than its forebear, and is organized differently. The Apostle and Apostle Spawns occupy the Demon Army, a group of valuable warriors whose inhuman abilities put them on par with the demonic armies of Emperor Ganishka. The mysterious Rakshas seems to be part of the Demon Army as well, but makes claims that he will slay Griffith when the Kushan crisis is over. Regular human beings from the Midlands, like Mule Wolcliff, was drawn to Griffith by his superhuman charisma and his reputation as the hero of the Midland blessed by the Holy See. They form the majority of his armies, much like the first Band of the Hawk was formed by young men trying to follow their dreams. The families of the soldiers are allowed to follow, and after reach battle, Griffith himself performs a ceremony to summon briefly the souls of the slain to comfort their surviving family-members.
Human beings with special powers or other means of usefulness, like Sonia, Princess Charlotte, and her maids are also allowed to follow, even if they take no part on the combat field. This purpose appears to be to form a liaison between the humans and Griffith's Hawks, another element of the commander's charisma. Kushan prisoners of war have a part as well. The new Band of the Hawk applies a policy of half-mercy over Griffith's enemies: when a Kushan army is defeated, survivors are given the choice to follow as prisoners, or be killed on the spot. The prisoners are sent to the front lines for the next three battles: if they attempt to escape, the Band of Hawk will kill them, but if they survive they're allowed to follow the Band as any other loyal soldier, with all the privileges of loot and the glory.
The general public seems aware that there's no continuity between the first and the second Band of the Hawk, however it is generally unaware of the final fate of the first Band and the demonic nature of the "inner circle" of the new formation. As the Eclipse remains a secret between Guts, Griffith, the God Hand and its Apostles, and the Skull Knight, the general public presumably believes that the Hawks met their demise or disbanded during the year long persecution following Griffith's imprisonment and Griffith returned later with new followers.
As the first Band held briefly the position of a named Army in the Midland Military, the White Phoenix Army, and Griffith held the noble title of the White Phoenix General, the second Band received, with the blessings of the Pope, the favor of the Holy See and Charlotte's constant presence around Griffith, similar privileges as the natural leaders of the Resistance against the Kushan empire.