I've been trying to figure out exactly when it is that I go "critical". It happens, I say "Oh good," but I have no idea why it happens. Is it based on how many pips? Is it gonna happen more often the higher level I reach? Are there conditions I can create? It seems so random.
A critical simply doubles the base damage (or healing) of the spell you cast.
If you check your Advanced Character Statistics in your spell book (hit "C" and select the second tab on the top), you will see a critical hit rating. Important: The number is not your chance to critical. If you hover your mouse over the number, a box will appear telling you your percentage chance to critical. It does not depend on pips, mana, health, or any other factor. It is simply random chance, sort of like getting a power pip. You can increase your chance to critical by upgrading your gear if possible.
There are guides out there as to how it is calculated, but to put it basically, as your level increases, your critical rating needs to go up if you want your percentage to stay the same. For example, my ice wizard is level 96 right now, and he has a critical rating of 278 with his questing gear. When I hover over the number, it says I have a 25% critical hit chance. Just a couple of levels ago (I think it was 91 or 92, something like that), if I hovered over my critical rating it said I had a 30% critical chance. The critical rating shown on the statistics screen didn't change (it is still 278), but since I am a higher level, I need to add more to that number if I want my critical percentage to go up.
On the same page where you see your critical rating, you'll also notice your Block Rating.
This simply indicates the % of blocking an enemy's incoming criticalled attack. It works very similarly to the critical rating in that, it is represented by a number value on the character sheet, but incorporates the use of a % mechanic.
So again, the % chances of blocking an enemy's attack decreases as you level. Also note that there is a rating for each school on the sheet, so if your block rating for for example is higher than your rating for , you can expect to block enemy's criticalled attacks a little more than you may a 's.
Critical/Block is an integral aspect of the game, especially as you decipher through the second arc.
Similarly to you, enemy's can also gain criticals and block them. They gain criticals more than they block though, but it does happen. (Especially bosses as you'd imagine)
I personally choose to invest heavily in my critical and forsake the block. Gaining a critical on a well buffed up spell can turn a boss' 40,000 + health into 0 quickly!
Criticals can happen literally almost anytime in combat, but you must have a critical rating on something your wearing. Say you have a robe that gives +12% critical rating that will then boost your chance of getting a critical doing double damage/healing. They do not require a certain amount of pips. Hope this helps
for example is higher than your rating for 
, you can expect to block enemy's criticalled 
