Funeral Parlor or Undertaker, literally translation of Sōgisha (葬儀社) is a resistance organization dedicated to liberate Japan and fight the government. Gai Tsutsugami is the leader of this group. Roppongi Fort is where their headquarters is based, a probable reason for the many young members enlist. It was basically a clandestine organization, hiding its presence, but revealed their existence as a response to the Roppongi Fort invasion.
Funeral Parlor was founded sometime after GHQ took over the Japan. The GHQ had asserted its dominance in the nation and began to strip its sovereignty as Japan had become more and more dependent on aid and protection from the outside world. This had caused GHQ to become more authoritative and corrupt as they set up various divisions to control the Japanese population. This eventually led to the organizaiton's formation and now resists the GHQ's rule over Japan.
During the events of the series, Funeral Parlor is seen attacking the GHQ whenever they see fit. Parlor members were first seen in episode one after a GHQ Battalion was sent to a nearby ghetto to whipoutt the local population after they were declared to be infected. Funeral Parlor interivnes and manage to push back the GHQ Forces from the area. Gai Tsutsugami had confronted one of the GHQ Majors and managed to kill him and saving all of the survivors. Shu Ouma is captured by the GHQ after one of his friends had ratted him out and was rescued by the organization and decides to officially join Funeral Parlor and joins them an episode later.
After Shu joins, he's then forced to go military training but is able to be a confident and reliabel soldier often helping Funeral Parlor on many occasions but is soon tramatizedd after he was forced to kill June, his best friend Yahiro's younger brother, he is unable to fight well and is forced into hiding until he is able to fight again. He eventually regroups with the Funeral Parlor when they began an attack against a GHQ Airplane but were soon ambushed and forced to retreat as the Apocalypse Virus was released and all surviving members had been scattered. After episode 13 the organization's status is unknown but is implied to have been dissolved since all remaining members have officially lost contact with each other and Gai was killed.
The remaining surviving members all regroup towards the end of the series to fight the GHQ and stop Mana Ouma from destroying the world after it's discovered that not only is Gai alive, but he's been revived and has now sided with the enemy both the GHQ and a secret organization called Da'ath. The survivors; Shu, Inori, Ayase, and Tsugumi with a few other remaining members then engage the enemy and manage to stop Gai but at there cost of Inori's life, Shu's health/fragile condition, most of the surviving Funeral Parlor Members, and having to kill both Gai and his sister in order to save the world. By the end of the series, all remaining survivors have scattered and live casual lives officially leaving the organization dissolved by the end with the GHQ defeated and the UN withdrawn from Japan.
Funeral Parlor is led by Gai as the organization's founder and leader. He leads the organization to victory in order to free Japan but he does it for a secret personal reason. Other commanders include Shibungi as the Staff Officer and Chief Advisor and other lower-ranking commanders. Everyone else are either low-ranking soldiers or other commanders/military officers. Shu is a very key member to Funeral Parlor due to his powers with the Void Genome and he has helped the organization win many battles.
Funeral Parlor is a Japanese Nationalist organization as they fight for the soul purpose of a Japan free from tyranny. The GHQ had been murdering innocent civilians and they act as the defenders of the Japanese people as their supposed defenders have betrayed them and left them for dead. They protect the innocent and due whatever it takes to defend Japan and free her from its oppressors.
Being a military resistance organization, Funeral Parlor has standard firearms and resources and are usually outgunned by the GHQ and their endless supply of weapons from the United Nations. Despite this however, Funeral Parlor was able to get and Endlave Mech which gives them and advantage in battle and Shu's Guilty Crown powers also give them an edge as he is able to outmaneuver the enemy.
- (Gai Tsutsugami to Major Guin) "The world always forces a choice on its inhabitants. "Survival of the fittest": that is the law this world operates by. We continue to offer funeral songs to the ones selected out. Hence "Funeral Parlor." The name signifies that we are always on the singing side--that we are the survivors!"