Oh but this Underworld continuity Shadow kind of has 3 separate types of fate haxes.
There's the popular one (Historical Importance Index) that gets introduced in SF3 which is what you guys are arguing about here.
And the second one is a dialed up to a hundred version of the first. Shadow gains it after he enters
Tenebris' Portal, causing him and humanity to "swap places" with Tenerbis and the other Eternals. It is here where Shadow gains the ability to wield the Threads of Fate similarly to how the literal
embodiments of
fate and Tenebris are capable of. Shadow can
manually decide which direction the next coil of life and death will take along the spiral of history. This profile is a bit outdated but I made a discovery recently in which characters who can see fate lines by default view the future. And with Shadow in this version being able to view anybody's fate line, I wouldn't be surprised if he could just see whatever Rein can pull off in the future and adapt accordingly via altering destiny.
And the last fate hax comes from Valentine's Day equipment created by
Fatum, with each being able to change destiny.
And to top it all off I could also just throw in there the Supernatural Luck granted to Shadow by him owning one of
Son of Heaven's coins, though how lucky he can get is never shown.