Surendranath Santaraksita was the Master of the library of Taglios who became a prisoner, and then ally, of the Black Company during Water Sleeps. He was a member of the bhadrhalok, a powerless group of high-caste Gunni intellectuals who opposed Soulcatcher's Protectorate in Taglios.
Master Santaraksita is given the first Annals of the Black Company by the Radisha Drah and told to destroy them, but he cannot. His unwillingness to destroy books would later allow the Black Company to recover them before they left the city to reanimate the Captured.
Santaraksita stumbled upon one of the young sweepers of his library, a boy named "Dorabee", reading. Unaware that this was Sleepy in disguise, he was stunned that somebody not of the priestly caste was capable of literacy. He tested Sleepy's aptitude on several occasions and tried to seduce her, still thinking she was male. In one incident, Master Santaraksita accompanied the library's gate man, Adoo, in search of Dorabee. Adoo led the old man near the warehouse of Banh Do Trang that was being used as the Black Company's secret headquarters, but the two were effectively immobilized by the "confusion net" of disorienting magic spells. Banh Do Trang notified Sleepy of the intrusion, and, Tobo successfully lured Adoo and Master Santaraksita out of the net to safety, protecting the group's anonymity.
Later, Master Santaraksita and the copyist Baladitya were kidnapped by the Company, and were forced to translate their older Annals. The Company brings the two elderly Gunni librarians onto the glittering plain and into the fortress with no name. Santaraksita was present with Sleepy, Goblin, Tobo, and Suvrin when they encountered Kina in person for the first time, in her prison chamber far beneath the fortress. They fled in abject terror when Kina attacked them with fiery wisps of sorcery. Goblin sacrificed himself, impaling Kina with the Lance of Passion, to buy them time to flee back up the daunting staircase.
Master Santaraksita joined the monks of Khang Phi after the Company reaches Hsien. At Khang Phi he finally finds the intellectual challenges and wise people he has always wanted to spend his days surrounded by. His last act as an ally of the Company is to help them steal the knowledge to repair Shadowgates from Khang Phi.