three. What would their character storyline be? What would be the consequences of the player following or not following it through?
ten. Would they have a range of possible endings? What would be their "good" ending? What (if there was one) would be their "evil" ending?
holy shit i got a little too into this. so i put this under a read more LOL. i'm also going to tag @x688plsloveme because i also ended up answering number 10 while typing up this ESSAY!!!!!!!!!!!
Diana would be a later-game recruitment in 4 that would rely on allying with the Brotherhood of Steel, her questline would be unlocked after the events of The Glowing Sea quest (or perhaps even an alternative) and leading up to Hunted/Hunter where you’re tasked with tracking down a courser. Quest name: The Last Sentinel.
You can unlock her quest either by passing a speech quest (earn yourself some AP!) with Danse about his own personal knowledge about coursers (pay attention to his body language/shift in emotion, this is only accessible if Danse is your companion during The Glowing Sea quest) or directly through Maxson himself once you’ve returned to the Prydwen.
Either Maxson will send you on an assignment to venture into the Capital Wasteland or Danse will off-screen request an assignment to the Capital Wasteland himself (oh, imagine all of the fun little side-quests/dialogue that you could get there — like for MacCready or Danse!) to convince The Last Sentinel to either:
A) Give advice on how to defeat a courser and where to find them.
B) Give advice on how to defeat a courser/Rejoin the ranks - Careful! You have to not only pass a high speech check with Diana herself, but you’ve got an even tougher Tunnel Snake to convince, too! (this is temporary, she will return to the CW immediately upon completion of Hunter/Hunted unless you pass a high speech check that will make her permanent)
C) Rejoin the ranks/Diana assists you as a temporary companion (becomes permanent* dependent on choices made during BB, *post-game will reveal that Diana has returned to the Capital Wasteland)
D) Evil option: Diana and these Vault dwellers have had it too nice for too long! Clean out the Vault! - Caution: This choice will cause you to permanently lose Danse as a follower and if you had a high affinity with MacCready, expect it to drop quite a couple points, too.
There are no consequences to the gameplay if you chose not to recruit her/or bypass the quest overall but it will directly affect Danse’s ending and can have some influence on MacCready, too.
I like to think that if you don’t pass the immediate speech checks with both Diana or Butch that you’ll likely be sent on a side-quest to build affinity with them, something likely related to assisting the Vault with some troubles outside of it.
Be warned: Sarcastic/Mean dialogue with Butch will result in a more challenging speech check later on. Interaction with Butch is highly dependent on who you have as a follower — it’ll be harder to convince him to let Diana leave with her ex standing over your shoulder!
Taking MacCready as your companion to the Capital Wasteland will unlock a side-quest related to Duncan. This will boost your affinity with MacCready, give you some XP and a decent reward, and unlock a special perk for MacCready.
Taking Deacon as your companion to the Capital Wasteland will unlock dialogue about Diana's pre-existing relationship with the Railroad (mind you, you will have to pass a speech check to do so) — if *secretly* Railroad-allied, you will be able to receive higher XP.
Taking Preston Garvey as your companion to the Capital Wasteland will unlock a funny little cutscene (to you, maybe! To Butch? not so much) — if *secretly* Minutemen-allied and finish Danse's secondary companion quest post-BB (that I've absolutely made up), you will receive the highest XP and reward.
Taking Nick Valentine will unlock some special dialogue but nothing further than that. (Think Diana is awfully fond of him and he knows exactly who she is)
Taking Danse as your companion to the Capital Wasteland will unlock a lot of special dialogue, as well as some future foreshadowing to his synth-xistence. Depending entirely on your actions post-BB, Diana will trigger another quest that helps Danse explore where he really began as well as assisting him in "finding himself" (aka, set him up with the Minutemen or allow that man to wallow in his misery). Setting Danse up with the Minutemen will boost affinity with Diana, *finally* unlock Danse's romantic relationship, and earn you a special new perk for Danse himself.
Diana will act as a temporary companion that will assist you during Hunter/Hunted but will only exist in the Prydwen up until the events of Blind Betrayal after that. Unlike Haylen being the one to reveal the truth to the player character, Diana will be the one that tells you about Danse being a synth and she will insist on joining you in finding him:
If you chose to deny Diana, you will have to pass a speech check to convince her to stay put or she will immediately become hostile. This will result in Diana's death.
If Diana joins you and you side with Maxson, Diana will immediately become hostile. Careful, she's tough, even with that bad leg of hers. This will result in Diana's death.
If you convince Diana to stay and side with Maxson, Diana will immediately become hostile upon boarding the Prydwen. This will result in Diana's death.
If Diana joins you and you side with Danse, your affinity with her will go up, you will unlock her as a permanent companion (now that she's been booted from the Brotherhood, too - unlike Danse, BoS will not immediately become hostile upon seeing her, but you will get a Diana disliked that! if you fast travel to the Pryden or assist the BoS in any way. This will also trigger a special cutscene between Danse and Diana where you can spectate their official break-up. If your affinity is high enough, Diana will give you her "blessing" but will be a neutral interaction. If your affinity is low you will get a Diana disliked that! and a rather rude remark from her about what you're doing.
If you convince Diana to stay put and side with Danse, you will trigger a special cutscene between her and Maxson on the Prydwen, as well as unlocking her as a permanent companion. You will gain no affinity with Diana with this option. Danse and Diana's break-up will occur off-screen. You will not receive Diana's "blessing" if you chose to romance Danse even if your affinity is high, it'll remain a neutral interaction, but expect a snide remark about your intentions.
Diana has no additional companion quest after this but upon achieving highest affinity with her, you will unlock a special perk (I don't know what it would be, this needs more thinking...)