I wanted to test this earlier (and confirm the things below to sate my own curiosity) but I was slacking a bit on getting more combat powerscrolls to test with, since I was reluctant to spend on 120 scrolls for weapon skills that I never intended to use since Archery is by far the best for general hunting. Anyways I decided to bite the bullet and do it, and then tested the various limitations of the Essences, so without further ado:
If you have been hunting Balrons, I am sure you will have noticed that they will drop some pinkish-purple vials every kill.
These vials will are Essences, and they can spawn for any of eight skills:
- Essence of Anatomy Skill
- Essence of Tactics Skill
- Essence of Archery Skill
- Essence of Swordsmanship Skill
- Essence of Mace Fighting Skill
- Essence of Fencing Skill
- Essence of Wrestling Skill
- Essence of Parrying Skill
Balrons are not the only creature that can drop Essences, Peerless are known to drop a small stack every now and then but by far the best way to obtain them (and a hefty chunk of gold at the same time) is to farm Balrons after you take into account the time taken to kill them and the respawn timers.
The primary use of Essences is to increase the above eight martial skills above their caps, to a maximum of +10.0 Skill Points over your current cap.
Each Essence consumed will increase the listed skill by 0.1 points.
The following examples will show what happens when you use varying numbers of Essences.
Anatomy will be used as the skill in the examples, the Essences work the same way no matter which of the eight skills they are for.
Scenario 1: (The normal situation to use Essences in)
You are at 120 "real" Anatomy skill, having consumed a 120 Powerscroll and trained it to 120 via combat.
You consume 100 Essences of Anatomy Skill.
Your Anatomy rises 10 points beyond your cap.
You are now at 130 Anatomy, the highest you can currently reach.
You may not drink further Essences of Anatomy, the game will not allow you to do so.
Scenario 2:
You are at 100 "real" Anatomy skill. You have not consumed any Powerscroll so your cap is 100 as well.
You consume 100 Essences of Anatomy Skill.
Your Anatomy rises 10 points beyond your cap, to 110 Anatomy.
You can not currently rise higher since Essences will not take you more than 10 points above your current cap.
You may not drink further Essences of Anatomy - since you are currently unable to gain from them, the game will not allow you to do so.
Scenario 3:
Following on from Scenario 2, you now consume a 120 Powerscroll.
You now have 110 "real" Anatomy skill, with a maximum cap of 120. The "bonus" 10 points of Anatomy are now effectively real skill points, functioning the same as if you had trained them via combat.
You consume 200 Essences of Anatomy Skill.
Your Anatomy rises 20 points, to the PS cap of 120, and then past it to 130.
You may not drink further Essences of Anatomy, the game will not allow you to do so.
Scenario 4:
You are at 100 "real" Anatomy skill. You have consumed a 120 Powerscroll, but not trained yet.
You consume 300 Essences of Anatomy Skill.
Your Anatomy rises 30 points, to the PS cap of 120, and then past it to 130.
You may not drink further Essences of Anatomy, the game will not allow you to do so.
I hope this clears up what you can and cannot do with the Essences.
End notes:
There were non-stackable martial skill Essences a while ago which were able to increase your skill by more than 0.1 points.
If you happened to save one of these, and used them when you were at 129.9 skill (after consuming 99 stackable Essences or many non-stackable ones) you would be able to rise a sliver over 130 in that combat skill.
A notable disadvantage of this is that your skill title would permanently be set to that of whichever skill was highest - you could not regulate which skill title was displayed out of the eight combat skills, by locking the undesired ones and having the desired skill-lock set to point upward.
Since these are no longer available this is not particularly important, but I felt it was worth including for posterity.
Please note that Elixirs (though they are incorrectly named "Elixiers" in-game) do not function like this, and will NOT take you above your skill cap (no matter what it is).
So even though you can obtain Elixirs for the combat skills, they will not enable you to rise over 120 skill, let alone 130.
Small update:
I tested drinking several hundred essences singly (0.1 skill gain each time), and they do not appear to be able to give you stat gains. This warrants further testing with a secondary character with lower skills since I'm almost out of possible gains on my main character.