|Weiss, you dumbass!|
SPOILER ALERT - Plot details for NieR follow.
Devola is a bard and is a regular performer at the tavern in Nier's village. Popola, her twin sister, is the librarian in charge of the village library. Both sisters are considered the leaders of the village and are always looking out for Nier's daughter (sister in RepliCant) Yonah during his frequent absences. Devola is the one who gives him side missions.
When the player reaches the Shadowlord's Castle, it is revealed that both Devola and Popola are androids working for Project Gestalt. The twins are revealed to have lived for thousands of years as a result of the initial experiments of the project, and have thus been charged with keeping eye on other experiments as a result: namely over the members of the entire party, including Yonah. They were made to provide support when the day has come for Gestalts to return to the Replicants' vessels. They are tasked with extracting data from Gestalts' souls, making new Replicants' bodies, and returning a dead Replicant's data to its Gestalt.
It is also revealed that the Sealed Verses originated from the experimentation on them both, stating that they only loaned Grimoire Weiss a fraction of their power, thus meaning that their magic and capabilities are far superior to that of Grimoire Weiss.
Devola dies in her sister's arms after being defeated by Nier.
Popola and Devola aid 9S in getting inside the Tower by serving as distractions to the machine enemies. After 9S fails at hacking his way inside, Popola makes an attempt at the cost of being perpetually electrocuted. Devola defends 9S and Popola from the machines until Popola manages to open the Tower's gate. Devola annihilates the machine she's fighting and drags 9S through the gate Popola opened, saying her goodbyes to 9S as the gate begins sealing itself again. As soon as the gate fully closes it, Popola receives a presumably fatal shock, which brings about a static screen.
A heavily wounded Popola is later seen with Devola by A2 at the Tower's entrance. They ask A2 if they managed to do some good, with A2 mentioning they had. The pair reveal to her that they have opened the Tower for 9S.
The NieR RepliCant × SINoALICE collaboration has both twins available as a potential character through the collaboration gacha. Their staff can be unlocked through a payment of 300 crystals. When the player uses the job class in battle, only one twin is randomly selected to fight. They do not appear as a team.
Their job story is a third-person narration of the twins' thoughts NieR:Replicant that is told in a fairy tale like fashion. Neither one of them understands why they were created to be sisters until they forced to bid farewell to one another. To live in such a cruel world, family would have been the only remedy for the loneliness they would have had to endure.
The twins' weapon story is a series of letters addressed to Popola. The last level has Devola writing her sister that she will be late coming home, telling her twin to not stay up waiting for her. Her twin happily accepts her concern.
"Ancient Song" is the first answer for the collaboration's Twitter quiz.
- Like Popola, Devola's name is a reference to the weapon Devolapopola (Skald's Song) in Drakengard. Additionally, according to a Drakengard guidebook, Yoko Taro liked the weapon story and wished to someday make them characters in one of his projects. The names were taken from two dogs owned by an acquaintance.
- According to Nier, when Devola drinks alcohol she becomes "very friendly". This is further demonstrated in the Drama CD.
- She is good at tying a cherry stem with her tongue.
- Saito conducted a Niconico livestream to promote Automata which included a character popularity poll for RepliCant. Users voted the twins to fifth place.