By consuming the Essence of the Manipulator, you gain several boons:
*You gain conscious control over your charisma. You can switch between being the most fascinating person in any room to having so faint a presence only the most attentive people will even notice you're there. You can also apply your charisma selectively, becoming a dazzling presence in the eyes of your targets while others would be unable to describe your appearance if questioned, and decide how they perceive you, if you seem charming or intimidating to others. You can also make your charisma fade in the minds of others, so that while they listened to you with rapt attention, over the span of the next few days they will forget the impression you left on them until they forget you completely. This however doesn't mean your words fade from their memory if you don't want to, instead they'll merely forget that the ideas you planted in their mind weren't their own.
*You become a masterful actor, able to play any role and present any personality you choose. You will instantly be aware of anyone attempting to read your mind or sense your emotions and can immediately create false thoughts, feelings and even memories that will show any mental scan exactly what you want them to see. You also gain great oratory skills both for simple conversation as well as in speeches before immeasurable crows.
*When observing someone you will within minutes gain a complete understanding of their mind, how they think, what motivates them and how they tick is revealed to you. You can read people like books, their deepest secrets and most hidden thoughts may as well be written on their foreheads. Their subconscious thoughts and biases can be revealed with but a glance. This also works on large crowds, though to a lessened extent when the crowd as a singular entity is targeted.
*Any person you focus on, you know how to remold them to your liking. You can break them with but a few words, you know how to tear down their ego, how to use cruel insults and sweet promises of relief to wear down even the most stubborn resistance. You can also uplift them, give them the greatest confidence in the bleakest circumstances. You can make the most stubborn and bullheaded man see reason, or turn the most open-minded and accepting person into a close-minded bigot. You turn people into simpering slaves completely dependant on you or manipulate them freely without them even being aware that you exist.
*You can also manipulate crowds of people on a larger scale, with only minimally less fine-control. You could lead a hopelessly-outnumbered force into a heroic charge without a single man breaking ranks, as well as demoralize a force with an overwhelming advantage to the point of making a well-armed army of thousands to take flight when charged by children wielding sticks. You can fan the population of a utopian society into complete revolt, or make the population of the most tyrannical dictatorship adore the boot that crushes them. Social engineering on all levels is child's play, you could start a political movement or even a religion and turn it into a universal belief, no matter how drastic or ridiculous. You can turn a noble caste consumed by greed and hedonism to altruism and selflessness, convert a group of radical feminists into a patriarchal faith preaching that a woman's reason for existence is to please men, or simply make the act of wearing a plate of cooked spaghetti as a hat into the latest fashion-trend. The time needed to mold others to your will depends on the extent of your change, from a few moments to encourage someone to act on their impulses, a few minutes to rally a group of men into an action they believe correct but lacked the courage, to a few days to completely reshape their world-view into something that goes against everything they were before.