Many Devas and Sages dedicated to Lord Balarama visited Him on the banks of Padmateertham according to a popular legend. They asked Him that they could be allowed to live there worshipping the Lord. Balarama bestowed his wish on them. Those Devas and Sages are believed to reside in Kallara B, worshiping the Lord. Naga Devathas devoted to the Lord also dwell in this Kallara. Kanjirottu Yakshi, whose enchanting and fearsome forms are depicted on the southwestern portion of the main sanctum, lives in this Kallara worshipping Lord Narasimha.Under this Kallara were installed holy objects such as Sreechakram to enhance the potency of Principal Deity. The Kallara B Protector is said to be Lord Ugra Narasimha of Thekkedom. On Kallara B there is an image of a serpent indicating danger to anyone who opens it. In August 2011, a four-day Ashtamangala Devaprasnam declared Kallara B "prohibited zone."
In 2011 the Observers appointed by India's Supreme Court opened the antechamber to Kallara B. But the Observers could not open Kallara B. Gopal Subramanium, however, recommended its opening after conducting another Devaprasnam in his report submitted to the Supreme Court in April 2014. The two Swamiyars in Pushpanjali are Padmanabha Swamy Temple 's highest spiritual dignitaries. On 8 February 2016, Naduvil Madhom's Pushpanjali Swamiyar sent letters to the Chairman of the Administrative Committee and the Executive Officer expressing his deep opposition to Kallara B's opening.The Munchira Madhom Pushpanjali Swamiyar led a Ratha Yathra campaigning against the opening of the sacred Kallara from Kasaragod to Thiruvananthapuram in May 2018. The supreme spiritual leader of Kerala Brahmins, Azhvanchery Thamprakkal, while addressing a meeting held in connection with the Ratha Yathra, also demanded that the opening of Kallara B should not trample on faith.
In 1680 A.D., Mukilan, a marauder, invaded huge parts of Venad. The Budhapuram Bhaktadasa Perumal Temple owned by Neythasseri Potti was demolished. Mukilan had plans to loot the vaults of Sree Padmanabha Swamy Temple and ruin it. But local Pathans loyal to the Venadian Royals dissuaded him from doing so. Padmanabhan Thampi, Anizhom Thirunal Marthanda Varma's arch rival, marched with his forces to Thiruvananthapuram and attempted to loot the Temple vaults.Thampi stayed at Sri Varaham, and sent his mercenaries to the Swamy Temple of Sree Padmanabha. It is said that hundreds of divine serpents materialized and frightened away the people of Thampi. Emboldened by that heavenly intervention, Pallichal Pillai and local people opposed Padmanabhan Thampi and made sure the mercenaries did not proceed with the misadventure.
Kallara B is highly unlikely to open after the 1880s. An article by Emily Gilchrist, a visiting Englishwoman in the 1933, recalls in her book 'Travancore: A Guide Book for the Visitor' about an unsuccessful attempt to open one Kallara in 1908: "About 25 years ago, when the State needed additional money, it was thought expedient to open these chests and use the wealth they contained." "A group of people" got together and attempted to enter the vaults with torches. They "fled for their life, when they find the vaults" infested with cobras.
These figures were based on the discoveries from the opening of five vaults in July 2011, with at least one remaining vault (B), which is the biggest, still locked. One of the oldest existing estimates concerning only Vault B, which can be considered at least as reliable as any since the discovery of the Temple's hidden treasure in 2011, was made by the Travancore Royal Family itself in the 1880s. According to it, the gold and precious stones contained in Vault B, which is by far the largest and the only vault (of the six reported) that has so far been unopened since the discovery of the treasure was worth INR 12,000 Crores in the terms of that time (1880s).Given the subsequent inflation of the rupee and the increase in the prices of gold and precious stones because, in general, the treasure alone in the unopened vault B will be worth at least 50 trillion (US$ 700 billion) in today's terms, without taking into account the cultural value. In the 1880s, when the inventory and estimate were last updated, the price of gold was INR 1.8 per gram (the price of gold was about USD 18 for an ounce in the 1880s when the dollar was 3.3 to the rupee). In fact, following these figures, the gold in Vault B could potentially amount to many more trillions of dollars even before the cultural or historical value is factored into.