Limit Break stuff

Critical Hits 
 

Every Combat Class has the capability to deliver a "critical hit" to mobs. These Criticals have a 1.2x damage modifier as opposed to a .8x~.99x damage modifier of standard hits. Even better, Criticals ignore enemy Pdef/Mdef. So, Assuming you have the same boosts, and your normal hits hit for 1051 damage versus a lost hua po, your critical hit will hit for 1357 damage versus the same mob. 

Limit Breaks 
 

Additionally, with certain sets (and the Limit Break Potions that DB Kano gives you, if you ask about his "kick-*** new move"), Combat Classes with high crit are able to abuse Limit Breaks. These Moves have a 1.5x modifier compared to even the 1.2x modifier of a critical hit. Even better, Limit Breaks ALSO ignore enemy Pdef/Mdef. Limit breaks are also the only way one can break the 9999 cap. However, being able to trigger a limit break does not usually mean you'll hit over the cap, if you don't have the boosts to begin with that allow you to hit high enough in the first place you will NOT break the damage barrier. 

Limit Break +Damage% 
 

There is also a new type of Damage boost, this is Limit Break +___% Damage. The only way to trigger this damage boost is to have a limit break occur. I don't actually remember if Limit Break +100% Damage is the cap for that boost, however, I will seek that out shortly. Update! Limit Break +100% Damage is NOT the cap. 

Damage formula appears to have been modified as follows: 

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Finally, yes it is possible to limit break on yourself, as the following screenshot demonstrates: 
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