Talent Essence (a.k.a Talent Points/TP) is the currency used for picking Talents from the various class trees available in Project Ascension. Players receive 1 TE per level, starting at level 10, meaning a level 70 character (Current Max Level), will have a total of Talent Essences to spend.
The counterpart of Talent Essence is the Ability Essence, which is used for picking Spells and Abilities.

To acess the talent tree, press the 'Character upgrades button next to the map, and choose 'character advancement'.
Investing in a Talent will require 1 TE per level you invest in. You don’t have to invest fully but you can for Capstone Bonuses. Capstone Bonuses allow bonus to certain talents such as Strength converted into hit rating, or the ability to gain Combo Points on critical hits.
Each talent has its own amount of levels, up to a total of 5.
Additionally, the Talent Trees also include ‘Talent Abilities’. These unique abilities are different from normal abilities. They’re more powerful and unique, due to this they require at least 1 Talent Essence along with the Normal Ability Essence.
Spending talent essence
Methods of Spending Talents are mostly as originally done in different Game Modes. (Free Pick, Wildcard, and Draft.)
You use the Talent Tree and Spend them as you like. If you would like to change your choices you can also use a Scroll of Unlearning for any talent to refund the invested TP.
Talent Abilities, however, are picked accordingly to each Game Mode. In Free Pick, you can freely choose anything you want so it’s not usually a problem. Nevertheless, in Wildcard and Draft Mode they are assigned randomly, so having an unwanted Talent Ability may result in wasted TP. You may re-roll them with a Scroll of Fortune.
To completely reset your Talents, you may use a ‘Talent Purge’. These will completely reset your picks and refund all TP spent. You start with 3 Purges like Ability Essence and when you run out everything costs varying amounts of Golds.
Like Ability Essence, there are ways to gain free Purges. By gaining Marks of Ascension and turning them into Nozdormu when at 0 purges, or heading to Chromie in a Major City by turning in her quest.

If you run out purges, you will have to pay gold for each time you purge. Use with care!