The Band of the Hawk began as a mercenary company led by Griffith. It was unusually disciplined, effective, and charismatic because Griffith inspired loyalty far beyond normal military command. Guts joined after being defeated by Griffith and became one of the band's greatest warriors.
Casca, Judeau, Pippin, Corkus, Rickert, Gaston, and many others formed the emotional core of the company. The Band was not only an army; it was a home for people who had few other places to belong. This is why its destruction matters so much.
The Band rose through war by winning impossible battles. Griffith's strategic genius, Guts's strength, Casca's command ability, and the loyalty of the rank-and-file made them legendary. Their success eventually earned them noble recognition in Midland, transforming them from mercenaries into the White Phoenix Knights.
For the campaign, the Band should survive as memory. NPCs may have fought beside them, been saved by them, envied them, sold supplies to them, or lost family to battles they won. Many people will not know they were sacrificed. Some believe they deserted. Some believe Midland purged them. Some think Tudor assassins took revenge. Some whisper that a curse followed Griffith.
Use Hawk relics as powerful emotional objects: a broken feather insignia, a pay ledger, a banner scrap, a helmet, a battlefield song, a letter home, a named grave that should not exist.