Arcane

Stormsurge

Stormsurge rewards successful burst: dealing heavy damage quickly triggers a bonus bolt and a speed spike — the item for AP assassins who chain targets.

Unlike a passive AP item, its value depends on your execution: if your combo kills or nearly kills, the bolt and speed convert the kill into a second one. On a poke mage chipping from afar, the passive almost never triggers.

First or second item for an ahead, roaming AP; avoid it from behind, where its passive stops triggering.