When upgrading the crystarium you'll get the option to unlock an ability. This is shown in the above picture, with the option to unlock the ability 'Fearsiphon'. My question is... Is it even possible to get a summary of what the actual ability does? As far as I can tell, there's no way to do this. It's pretty frustrating. How am I meant to choose what to unlock when I have no idea what the abilities will do?
I dont think you can, alot of those things there are passives that increase your resistance to spells and stuff, for the most part though i dont think you get an explination.
Wiki it. Fearsiphon - Recover 1/10 ATB gauge when attacking a staggered opponent. http://finalfantasy.wikia.com/wiki/List_of_Final_Fantasy_XIII-2_Abilities
It's not Mass Effect, broseph. Honestly, back in the day I never knew what the abilities meant other than conveyance via the name. Here I was like "I guess it helps this paradigm out!"
Also, the ability selection for crystarium expansion in 13-2 is a short list to choose from that is fairly easy. It can be a atb gauge extension, a role benefit increase, or a role unlock. Stuff like that fearsiphon is on the static path it follows. So in this case (after selecting a benefit from the expansion) the first Ravager ability you would get would be Fearsiphon. Unfortunately I don't think there is anyway in-game to know what the abilities do before getting it. But again since it is a set path you just need to be concerned in what role you want to be leveled up, there is no real aiming for or avoiding an ability.