As part of 's main questline the Sole Survivor will come into contact with many different groups and factions, some of which can be joined. While it is expected that the main factions of the Commonwealth will force a decision between them at some point, the Brotherhood of Steel has an addition choice as part of its questline. However, after rising through the ranks of the military style organization, revelations about Paladin Danse mean that the Sole Survivor has a difficult decision to make.
In order to get the quest the Brotherhood of Steel will need to be joined and their questline followed. After helping Danse and his team at Cambridge Police Station, the Brotherhood's main forces will arrive on the Prydwen after the main quest. From there, the Sole Survivor can complete plenty of radiant quests for them until it is time to gain access to the Institute.
There are some great factions in Fallout 4 with a mixture of new and returning groups for the Sole Survivor to meet and potentially join up with.
In order to trigger the Brotherhood must be the faction to help the Sole Survivor teleport into the Institute during the quest and be given a holotape to steal Institute data for them. Completing and giving the holotape to Proctor Ingram will let the Brotherhood have some very surprising data surroundingcompanion Paladin Danse. The Brotherhood quest will continue with after which Elder Maxson will want to speak to the Sole Survivor about something very serious.
Although not stated in dialogue or the quest details, it is best to take Danse as a companion during as if he is not the current companion his affinity score will drop to zero.
Maxson will reveal that the data from the Institute shows that Danse is actually a Gen 3 synth, and will order the Sole Survivor to track him down and kill him. Finding Danse is quite easy, as after speaking with Proctor Quinlan, Scribe Haylen will privately beg for Danse to be given a chance before revealing his location. The bunker
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