Arcane Blast now builds a 15-second window

Arcane Blast used to be a spell you chained into itself. After the redesign in Blizzard’s 16 October beta development notes, it is closer to a setup spell with a clock attached.

The new rules

• Arcane Blast is a 1.5-second cast.
• Each cast grants the Mage 15% of their Intellect as additional spell damage. This stacks up to four times.
• Each stack still raises the cost of Arcane Blast, as before.
• The effect now lasts 15 seconds from when it is first applied, rather than ending at your next spell cast.
• The mana cost is unchanged, but Arcane Blast’s damage and spell damage coefficients are both reduced by 40%.

A window, not a refresh

The phrase that matters is “from when it is first applied”. The 15 seconds start with your first stack, and the notes give no indication that later stacks restart the timer. Building to four stacks spends part of the window on Arcane Blast itself.

The other change is what happens after. The bonus no longer disappears when you cast a different spell, so you can stack it and then spend the remaining time casting something else with the extra spell damage.

What to plan around

Stack count and timing are now a trade-off. More stacks mean more spell damage but a more expensive next Arcane Blast and less time left. Blizzard has not published a recommended sequence, and the notes do not say which of your spells the bonus affects most.