After the mass burial, a period of optimism came over the Berserk Gang.
The elaborate mass burial was both a strategy by Aragorn to honor the dead warriors who sacrificed their lives in the previous war, and also a way to form the foundation for a sense of camaraderie within the new Berserk Army.
Compared to when the Berserk Gang just started fielding less than 5,000 mystic warriors, now the gang was a behemoth with over 200,000 mystic warriors.
Though the gang already swallowed them all, digesting them all was difficult and was why Aragorn took advantage of the mass burial to subtly effect it.
During the war, they were parts of different gang armies, but after the war, they became one. Becoming one was just in an official sense, it was not easy for warriors who pledged to a certain banner to switch loyalty so easily.