been thinking on Borderlands Vault Monsters and Sirens, and my brain came up with an au i really liked, so i'm sharing under the cut (btw, i haven't played new tales nor 4, so i won't be talking about the vault monsters from those)
Vault Monsters are Sirens AU
Okay, so the base idea for this AU is that every Vault Monster we encounter (with the exception of the Sentinel) is actually a Siren heavily modified by Eridian scientists or whatever equivalent they had. This also means there used to be a lot more Sirens before they became Monsters and their powers never got passed down, eventually reducing their number to 7. As for each specific Vault Monster/Siren...
The Warrior
Originally the user of Phaseflame, which allowed her to generate and control fire and heat. Made as an initial response to the Destroyer, the Eridians made sure to restrict her freedom when changing her, to the point of forcing to obey her handler/master's orders.
The Traveler
Originally the user of Phasetravel, said user could teleport over short distances instantly. One of many Vault Monsters made simply as guardians of treasure, the Traveler swiftly rebelled and teleported herself and her Vault away, only said Vault reacted badly to Phasetravel, and didn't stop teleporting until Gortys managed to jam that side of the Traveler's powers.
The Rampager
Originally the user of Phasechange, it allowed her to transform her body in a somewhat limited manner, with the ultimate purpose of making her more powerful. This power got severely limited in her change into a Vault Monster, only allowing her to transform within certain parameters, much unlike the greater freedom her original power granted.
The Graveward
Originally the user of Phase Horizon, which essentially allowed her to create mini-black holes. This ability got butchered when she was changed, limiting it to a passive effect she had on the planet she was in, basically turning Eden-6 into a "gravity sink".
Gythian
Originally the user of Phaseheart, it both gave her a greatly extended life (useful for a human Siren, useless for an ageless Vault Monster), and allowed her body and conciousness to live past her physical death (only useful as long as her body wasn't crippled or destroyed).
And finally...
The Destroyer
Originally the user of Phaseruin, which is similar to Phaseleech in that it allows the user to steal others' power and energy. However, unlike Phaseleech, which both can act as sustenance and allows the user to steal other Sirens' powers, Phaseruin simply directly transforms the victim's energy into power for the user. The Destroyer was the first Vault Monster made, and used by the Eridian leadership to eliminate their enemies and rivals. However, the Destroyer grew too strong and rebelled against her masters, seeking to take the power of the entire universe.
As for what this means to the storyline of the games? Essentially, when a Vault Monster dies, their powers are finally passed down. This usually happens to the nearest non-Siren woman to them. As such, the inheritors of their powers are:
The Warrior: Gaige
The Traveler: Sasha
The Rampager: Moze
The Graveward: Aurelia (she survives in this AU)
Gythian: Iris (who gets to come back through Gythian's power)
The Destroyer: Ava
That's about as much as I've come up with so far, but I'll probably come up with more at some point. Cheers!









