Mechanics of Guard BreakEdit
Each character has an invisible number of points (called Breaking Point for now). The number of points heavily depends on which character is used, some characters have high Breaking Point and others having low points.
Another invisible counter (called Blocked Attacks for now) keeps track of how many attacks the character succesfully guarded. When a block is attempted, the game compares Blocked Attacks to the Breaking Point of the defending character. If Blocked Attacks is higher, Guard Break occurs and Blocked Attacks is reset to 0. If Breaking Point is higher, the block occurs normally and Blocked Attacks increases by one.
It should be noted that every character has several pre-determined amounts of Breaking Point , any of which can be randomly chosen for the comparaison with Blocked Attacks. This makes the occurence of Guard Break random, though the more attacks are blocked, the more likely is it to happen. There is also a 1/4 chance for this comparison to be skipped entirely, meaning it's possible, though extremely unlikely, for a character to never Guard Break even after blocking many attacks.
The Blocked Attacks counter is reset only after being inflicted with Guard Break, and not after the end of every blocked combo.
Causes of Guard BreakEdit
Guard Break can only be inflicted by certain artes possessed by specific characters. There are some specific artes present in ACS that can raise Blocked Attacks faster than others while there some artes that do not raise Blocked Attacks and will never be able to cause Guard Break no matter how many times they are used. Also, there are some attacks that inflict Guard Break immediately.An important note is that you NEVER will be inflicted with Guard Break if you're airborne, but that DOESN'T mean guarding airborne doesn't raise your Blocked Attacks.