All champion abilities can be set to quick cast using the in-game options screen.
Quick cast automatically casts the selected ability at (or towards) the current mouse cursor position, as if you had first pressed the ability button and then left-clicked at the target position. Quick cast works for self-buff abilities, targeted abilities, ground-targeted abilities and skillshots. Quick casting a support buff ability (an ability that can be cast on yourself e.g. a shield or a heal) when the cursor is on an invalid target will self-cast the ability instead. Note that you can use self-casting to self-cast support buff abilities regardless of cursor location. Using quick cast can be invaluable because it reduces the time delay between activating and casting by cutting the user input in half; activate vs activate and click.
Remember that quick casting means you don't get the targeting graphic, which can make it harder to accurately aim skillshots. They will fire instantly, instead of showing the skillshot for fine tuning the shot. However, there is an option to turn range indicators on, which will show the targeting graphic while the ability key is pressed. This can also be helpful because the ability can then be canceled by right-clicking.
List of abilities that quick cast
The following abilities automatically employ quick cast:
- Ahri's Spirit Rush
- Cassiopeia's Noxious Blast
- Fizz's Playful and Trickster
- Irelia's Transcendent Blades
- Karthus's Lay Waste
- Riven's Broken Wings and Valor
- Urgot's Acid Hunter
- Vayne's Tumble
- Yasuo's Steel Tempest
- Zyra's Rampant Growth
- Nidalee's Pounce
Quick cast for special skill shots
Complex skill shots, such as vector skill shots like Rumble's The Equalizer, and Viktor's Death Ray, can be quick cast by holding down the quick cast hotkey to mark the beginning of the line, and releasing the hotkey to cast.
Tapping the quick cast key normally will result in a straight forward skill shot fired in the same direction as the champion.