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Shard of Hope
After Elizabeth Midford is kidnapped by Drossel Keinz, Ciel Phantomhive attempts to find her alone. Grell finds Ciel and Pluto after the latter made his "hunk radar" go off, and teams up with the pair after Ciel promises Grell can kiss Sebastian Michaelis if they help him find Elizabeth. Grell first aids Ciel by explaining him who Drossel is. Then, they follow Ciel and Pluto into the Mandalay Manor. However, once inside, as they have to use scissors instead of their regular Death Scythe, they have a bit of a problem with cutting down the well-made dolls. Ciel abandons them briefly, leaving them to fend off the dolls while Ciel attempts to find Elizabeth on his own.
Shortly thereafter, Grell makes their way out of the mansion with Pluto, and they meet up with Sebastian. They discover that Elizabeth is in a sealed tower around the back of the mansion. Grell charges in with Sebastian, Pluto and Ciel, but, fearing injury, Grell don't help much until Sebastian specifically requests their aid.
When they finally leave, Grell throw themself at Sebastian in an attempt to get their promised kiss, but Sebastian ducks out of the way resulting in Grell falling onto the floor face first. Ciel discusses taking revenge for Angelina Dalles's murder, prompting Grell to flee stating they will have to collect their promised kiss another time.
Book of Doomsday Arc
Grell are sent to Earth to retrieve a stolen Cinematic Record, on William T. Spears's orders, and after getting tired, fall asleep so deeply, some humans believe they are dead and they send Grell's "corpse" to Undertaker. When Ciel and Sebastian arrive at the funeral parlor to get more information, Grell tag along, and sneak into the cult's convent with them, in order to investigate further.
While inside, Grell identify the priest's Book of Doomsday as not being the stolen Cinematic Record, but try to get closer to him anyway by impersonating a child to join the Heaven's Choir. However, they are not capable of doing so, and Ciel is left as the only one of the three who can successfully go undercover.
Shortly thereafter, when Angela Blanc appears and kidnaps Ciel. Grell helps free Sebastian from Angela's use of the Cinematic Record to tie him up. Then, Grell and Sebastian charge after Angela, chasing her to the Grim Reaper library. They aid Sebastian and William in the subsequent battle against her, using a borrowed Death Scythe to help pin Angela up against the wall. However, when she aims to destroy the place, they are forced to flee.
Conspiracy and Revenge Arc
Grell show up in the burning London. They are shown initially mocking the dead (minus a still living baby they find and remorsefully state that they can't help), but then get to work helping to reap the many souls, along with Undertaker and William. At this point William returns Grell their original Death Scythe, something that Grell are extremely pleased by.
Grell appear atop a building in London, saying that "the end of this dance signals death." As a young woman named Ellen seems to spontaneously combust, Grell comment on her burning death. Later, as Sebastian is chasing the arsonist Mrs. Turner (the one responsible for the death of Ellen, among others), Grell attacks him. Sebastian asks why they have not collected the souls of the people Mrs. Turner has set on fire during her run through London, using a flash camera and magnesium powder. Grell first flirtatiously reply that they only want to capture Sebastian, but then explain that their death list states they are only after Mrs. Turner's soul, who will commit suicide five minutes after midnight. In addition, they tell Sebastian, that they could not have collected the other victims' spirits, as the heat of the magnesium flames is so intense that it consumes not just the body but the soul as well.
Sebastian secures Grell's help against the arsonist with flattery, saying that Grell will make a much better model for photographs than Ciel. They are delighted and gladly work together with Sebastian to find Mrs. Turner, who has Ciel atop Big Ben. The clock strikes midnight and the Grim Reaper and demon rush to the top. Seeing the camera, Grell start to pose for it as they are immune to the effects of the flash due being a Grim Reaper, with an impassioned speech about how women, like fruit, become more beautiful as they ripen with age, and declare himself to be the "Queen of all fruits—the Mangosteen."
Five minutes after midnight Mrs Turner starts to burn and dies, and Grell are very upset, since the soul they had to collect has been burned away. They remark that William won't be happy, but before leaving to tell him, Grell take a picture of Sebastian and himself using Mrs. Turner's camera.
When Alois Trancy is dying from his stab wound, Grell goes to collect his soul. Upon meeting Alois they look up his history and reveal that Alois is actually poor boy named Jim Macken and that Hannah Annafellows is a demon. After briefly struggling with her, Grell are able to stab Hannah through her stomach with his chainsaw only to find themself soaked in blood and alone with Claude Faustus. Claude asks if Grell is going to take back the soul they stole and whether they are allied with Sebastian Michaelis. Grell respond that they will just sit back and watch as "things have gotten interesting."
After Claude managed to combine Ciel's and Alois' souls and steal Ciel from Sebastian, Grell follows Sebastian around with a camera, photographing him until the annoyed demon forces them to stop. Sebastian gives him Mongolian salted tea with far too much rock salt in it to retaliate, but then promises to strike handsome poses for Grell's camera to make Grell kill the Demon Triplets with their Death Scythe.
During Sebastian's trip through the maze of Alois Trancy's heart, Grell briefly helps the demon. They use their Death Scythe to cut the vines constricting Sebastian, but only after Sebastian openly glared at them for wanting to take another picture of him. Grell is later used as a sacrifice for one of the questions after they are lifted up by Sebastian and thrown by him. Due to the explosion Grell are burned and knocked out, however they show no signs of anger and appear more than happy to have helped.
Later on, William and Ronald reap souls while Grell just yawns and stretches off to he side. Then they sense Sebastian and quickly turn to face him with a blushing and extremely happy face. Much to their surprise Grell instead find a table that is set with three cups of tea for them, William, and Ronald, and a candy center piece. The tea is supposedly Mongolian salted tea minus the addition of the rock salt, as Sebastian states that the tea was something that Grell would enjoy.