Aftercast delay is the period after successfully activating certain skills, during which certain character animations and skill effects are still taking place. This usually happens so character animations can finish playing, and so they are common for skills that have character animations, but usually non-existent for those with instant activation and no character animations (regardless of other visual effects).
Some skills respect aftercast delays, while others override them.
If a skill includes an aftercast delay, the next skill that respects aftercasts delays activated during the delay will be delayed and queued to be used after the aftercast delay ends.
Some skills will not only prevent activating other skills, but also moving while the aftercast completes, although those aftercasts can often still be cancelled with certain stun breakers.
Skills overriding aftercast delays sometimes cause parts of some skills to fail if they are activated before the aftercast completes, if any part of the skill happened during the aftercast (e.g.: Essence Bolt, Pyromancer's Puissance on Lightning Hammer's autoattacks).
Although there's no guaranteed way to know if a skill will respect the delay of another skill or cancel it other than trying, some patterns repeat often in skills:
- Skills part of an autoattack chain will override the aftercast of the previous skill in the chain, making the chain animation more fluent, but other skills interrupting the chain may not override their aftercasts.
- Single-skill autoattacks like Long Range Shot will have aftercasts that can be canceled by any other skill, including itself, or no aftercast at all, which allows using them more fluently without having to wait for the full animation (e.g.: The ranger will fire Long Range Shot again without the part of the animation that readies another arrow).
- Skills that break stun or force player movement like Burning Retreat and Lightning Reflexes will almost always override aftercast delays, activating instantly.
- Skills with no activating time but character animations like Frozen Ground will usually respect aftercast delays, but have no aftercast or very short aftercast themselves.
- Stowing weapons can cancel any actions and aftercasts that are cancellable with the Esc key.
- Swapping weapons always cancels all actions, skills and aftercasts from any skills in use, not only weapon skills, unless it is done from the Hero Panel.