Sigil of Superior Blood
30% Chance on Critical: Steal Health (This effect cannot trigger more than once every two seconds)
The actual cooldown appears to be five seconds, not two.
Testing: I’ve gone to the PvP lobby, got high-precision equipment and the sigil, and started hitting Target Golems, using the Mesmer Greatsword auto-attack to generate plenty of crits.
The closest interval between two leeches I observed was around 5 seconds.
I’ve done enough tests to reject the null hypothesis “cooldown = 2 seconds” with p < 0.0001. There’s also talk on the wiki where others observed the same.
Please update either the sigil or the description, thanks