If Zeratul
(1) takes Sentenced to Death at 16 and Twilight Falls at 20, and
(2) casts W twice,
(3) with the second W cast before the first W explodes,
any damage between the first W explosion and the second W explosion will receive an extra 25% damage multiplicatively. My working theory is that this is due to Sentenced to Death applying twice.
For proof, see this Twitch clip:
clips.twitch .tv/SuaveOnerousPotPMSTwin-RJH5La6kO5FxfG-K
The last 2 instances of damage done by Zeratul to Lili are between the first W explosion and the second W explosion. They are (1) an autoattack damage and (2) the second W explosion damage.
The autoattack should result in 553 damage
Base AA damage at level 22 is 298.6
Zeratul has 25% bonus from Sentenced to Death, 30% bonus from Psionic Strength, and 30% bonus from Might of the Nerazim.
298.6 * (1 + 25% + 30% + 30%) = 553
But it actually results in 691 damage, as Sentenced to Death applies twice multiplicatively.
298.6 * (1 + 25% + 30% + 30%) * (1 + 25%) = 691
The second W explosion should result in 882 damage.
Base W damage at level 22 is 568.8.
Zeratul has 25% bonus from Sentenced to Death, and 30% bonus from Psionic Strength.
568.8 * (1 + 25% + 30%) = 882
But it actually results in 1103 damage, as Sentenced to Death applies twice multiplicatively.
568.8 * (1 + 25% + 30%) * (1 + 25%) = 1103