Sheltergod "Shell" Thropp is the younger brother of the witches Elphaba and Nessarose, who later becomes the Emperor Apostle of Oz after the deposition of the Scarecrow. He is an antagonist in Gregory Maguire's Wicked Years.
In the Novels
Wicked
Shell has his debut appearance at end of the novel. He is seen comforting Frexspar, his father who explains that Shell was named after the lover of both his parents: Turtle Heart. It is implied that he most likely would have been Melena's favorite child simply because he was born a boy.
Son of a Witch
Shell, now working in espionage, is seen when Liir wants to enter Southstairs, a high security prison in the Emerald City. He claims to undertake in 'missions of mercy' in Southstairs, which involves comforting female prisoners by injecting them with poppy flower extract and having sex with them as payment in order to get information out of them. He helps Liir reach Chyde the Under-mayor, then leaves. Later, when Liir and Trism are at a bar before the former prepares to leave for Quadling Country, they encounter Shell outside the bar.
Claiming rights of ascendancy through the skillful manipulation of the palace's power brokers, and an "unfortunate accident involving a beaker of lighter fluid", Shell replaces the Scarecrow as Throne Minister of Oz.
When Liir reaches Kiamo Ko, Nanny tells him more about Shell. She says that he was always a troublemaker in his youth, like "tomorrow's stitches in yesterday's britches", and that he was a brilliant liar.
Later on, it is revealed that Shell, claiming to have experienced "the Awakening", where he heard the voice of the Unnamed God telling him to lead, crowns himself the "Emperor Apostle of Oz"; having done this through a force of formidable piety and a sacred election. The public think of him as being sincere in his faith, however Liir thinks he's a charlatan. In his political campaigns, Shell refers himself as an extremely righteous and pious man, but his military tactics are merciless; going as far as using dragons to terrorize the citizens of Oz into submission to his authority.
A Lion Among Men
Though not physically appearing in the novel, it is revealed that Shell, as Emperor, has the right to re-annex Munchkinland back into Loyal Oz. He also claims to be the rightful Eminent Thropp, due to the death of his older sister Nessarose. However, the role of Eminent Thropp would actually fall to his other sister Elphaba's granddaughter, Rain; his great-niece, of whose existence he is unaware.
Shell is also fervently searching for the Grimmerie, with hopes of using its power to aid him in his conquests. It is rumored that he has a single page in his possession, the page which Elphaba gave to the Wizard back in the first novel.
Out of Oz
In retaliation for a sortie of Munchkinlander guerrillas into Loyal Oz, Emperor Shell authorizes the imminent invasion of Munchkinland for the purpose of taking possession of Restwater, Oz's biggest lake.
Shell continues to look for the Grimmerie and has built up and trained more dragons for war. His search for the Grimmerie is shared by Munchkinland's new Eminence, La Mombey. He later declares himself Divine - the Unnamed God in the flesh, and resorts to calling himself in the third person, "His Sacredness".
Upon the discovery of Tip actually being Ozma Tipperatius, Shell willingly abdicates the throne and hands the power to Brrr as Throne Minister until the princess comes of age to rule. Shell later disappears from public eye and travels off to the Great Kells of the Vinkus where he will spend the rest of his life as a hermit.
In the Musical
Shell's character is omitted from the musical adaptation of Wicked, as Melena is stated to have died while giving birth to Nessarose.