Each spell has a set amount of concentration required and amount of mana required to maintain it per tick. This is based upon the spell and is
not in any way tied to level.
Your concentration is a set value based upon your current condition, see below, and your intelligence. The higher the intelligence, the higher the concentration value.
Conditions: Sitting adds to your concentration, resting reduces is slightly, and sleeping reduces it immensily. Effects that reduce your concentration are either those that reduce your intelligence such as feeblemind or charm, but also combat related instances. For each person engaged with you directly your concentration is reduced slightly, so you can hold a set of spells with three attackers but possibly not with five or six. Certain skills such as trip and bash have a momentary dip in concentation that lets up after the effect takes place. Certain spells such as hellfire, if it strikes you, momentarily reduces your concentration considerably. And finally taunt reduces your concentation for a decent bit of time.
When your concentation is reduced so that a spell is lost, i.e. you only have 8 points of concentation but were holding 10 points, the spells with the highest number on your "release" list will go first.
Code:
release
oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
o # Spell Casted On Concentration o
o===-===-===-===-===-===-===-===-===-===-===-===-===-===-===-===o
o 1 charm person Derk Thoms moderate o
o 2 detect hidden Yourself light o
o 3 detect invis Yourself light o
o 4 fly Yourself moderate o
oOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOoOOOo
You will first lose flight, then detects, then the charm. This assures that certain spells such as airy water are released last.
I hope this clears up a bit about how concentration works in SK, to my investigation. Feel free to correct me where I am wrong those who know better.