Saturn, the planetary ruler of Uttara Bhadrapada, is the emblem of control. If we really want full control over ourselves, we actually have to squeeze out and kill any potential that our ego has to rebel. This is why Uttara Bhadrapada nakshatra (located in the center of Pisces Rashi) represents the solidification of the Kundalini in the Ajna (Third Eye) Center, thus creating a special sacred mark on the forehead, which is the Crown of Glory signifying that one is a full adept. Reflecting Uttara Bhadrapada's rulership by the Serpent Deity, Ahirbudhnya (which is of a different category of serpent than those in Ashlesha nakshatra), in Egypt, this stage was represented by the Uraeus Serpent worn on the crowns of the Pharaohs, signifying that they were a God-King and had full control over the Serpent power (their sexual animal nature) and were thus fit to rule. In Western Occultism, reaching the stage of the Ajna means accepting the "mark of the beast", and signifies that you now participate in the Sabbath (The Day of Saturn) of the adepts. If you consider the relation of the Serpent to this nakshatra, and this nakshatra's achievement of the Ajna Center, this is essentially where the Serpent achieves wings and becomes a Dragon. The Serpent laying flat in Ashlesha has now been fully lifted from the ground-- now flying. A priest of the one, true, Universal religion is called a "Dragon" in Western Occultism.
This cosmic stage is well beyond ambition, achievement, and even practicing austerities, all of these activities reaching their highest point in the sign of Capricorn, while Uttara Bhadrapada shows the final solidification of the Kundalini in the Ajna Center, meaning that a person has already given up all ambition, effort, and sense of achievement, utterly squeezing out every drop of the ego and even limited human identity. Someone at this COSMIC stage is, for all intents and purposes, a "dead" person and no sensorial thing can inhibit their will. So, in the after-death state, when food, sex, anything is presented to them, it doesn't override their will. This is why it is the final completion of Saturn, as they essentially have the mark that Saturn has reached full maturity. They don't have to discipline themselves anymore because they are perfected. This is why the Ajna Center is associated with Siddha Loka which means "Realm of the Perfected Ones". It is very different than Jana Loka, the realm of knowledge and located in the throat center, which is associated with Jupiter and the Ether Element. To become a Siddha, one must pass through the spiritual stage of the 11th house, where they distribute all of their accumulated merit in order to go beyond knowledge and even good deeds, and reach the non-dual realm of the adepts. This is essentially the task of Purva Bhadrapada nakshatra, cusping Aquarius and Pisces & ruled by Jupiter, signifying the emptying out of all of one's merit and knowledge in order to transcend Jana Loka. In Western Magic, this Grade is known as Adeptus Major, which corresponds to Jupiter, where the task is to cross the abyss-- liquidating all of one's attainments, health, wealth, prosperity, and knowledge. The fact that Jana Loka is located in the throat is symbolic of why Kali holds a severed head & why Chinnamasta beheads herself; this is always the emblem of the Siddha's because it's a symbol of transcending the throat center. At this stage of Saturn's perfection, Kali, the Mahavidya associated with Saturn, changes from her form as Dakshina Kali (the Kali of the Right Hand Path with her right foot forward) to Shamshan Kali (putting her left foot foward), showing that this is the initiation of full left-hand path worship.
Considering Astrological Physiognomy and how this Ajna emphasis plays into the native's appearance, if you look at the appearance of some Uttara Bhadrapada Moon natives below (Moon ruling the face) they have uniquely rounded and pronounced foreheads, which result in celestial wide-set eyes. This is similar to how the final Mercury-ruled nakshatra, Revati, frequently grants its moon natives with a pronounced lower lip; the "Aim" bija (Saraswati, the Goddess who embodies all perfection of Mercury) is correlated with the lower lip during practices like Mantra Purusha.
image credits: By S.shanmugavel [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons