[quote]2. The left slot looks to be the grenade he uses and the right the warlock ability, wonder if you can use any ability in any slot[/quote] Given the above image of a print from E3, it seems each class will have one or more "grenade" type abilities with infinite uses on a cooldown equippable in the "left" slot, usable with L1/LB, and a more "expensive" ability with a longer cooldown that you use by holding L1/LB and pressing R1/RB. I'm guessing then that we'll be able to "ready" that grenade ability by holding L1/LB or possibly even "cook" it, which would be great. All the abilities are listed on the controller in black but some of them, like the Warlock's Glide, are additional button functions, in this case on the jump button. This is probably just showing the default controls and abilities for this gameplay demo so we might see other swappable or equippable abilities for each class in the future, but it seems they'll likely follow this "grenade/magic/movement" convention as far as ability types, each with its dedicated slot/button or button combo.