The Black Flash ability now has a different effect; instead of marking targets in front of the player with black flash sparks, it will instead put the player into a "Focus Mode," which allows you to hit a Black Flash.

Focus Mode (FM) does not change any abilities or increase any damage, but it will allow the player a chance to land a Black Flash. How would this work? When FM is in effect, players must reach a damage threshold, where FM will end, and you will be allowed to use Black Flash (ability) again after a long cooldown. When the FM threshold is reached, the next FM threshold will be decreased, the cooldown for the next FM will decrease slightly, and the Black Flash chance will increase slightly.

When a player hits these FM thresholds, they will have a chance of landing a Black Flash.

So let’s say the first FM threshold is a massive 55 damage, then the next 45, and then down by 10 damage pts each time. The minimum would be at 10 damage, and at that point, the damage threshold is so low and the chance for Black Flash so high that players can pretty much hit black flash a few times in a row, like in the actual source material, while still making it feel important.

After you reach the 30 damage threshold FM, if you don’t land a Black Flash, it will regress you one damage threshold, back to 40. After a certain amount of time, FM will regress naturally back to its original state and Black Flash chances.

Black Flash threshold is doubled against non-player/non-gojo/sukuna/shrinespirit entities for balancing.

Black Flash will now regenerate 750 CE and reset your RCT cooldown.

Threshold (damage) | Chance | Cooldown
55 / 10% / 60s
45 / 15% / 52s
35 / 22% / 44s
25 / 30% / 36s
20 / 45% / 28s
15 / 60% / 20s
10 / 80% / 10s

Sparks of Black Trait rework:
Sparks of Black will now halve the cooldown of Black Flash, allowing you to progress Focus Mode tiers more quickly. The special Black Flash is still implemented.
Black Flashes from Sparks of Black regenerate 500 CE and do not reset the cooldown of RCT.

Haphazard Flashes Vow rework:
Black Flash cooldown becomes random, and the Black Flash chance is set.
(35 damage, 25% chance.) Cooldown becomes random between 10s-60s.

Sparks of Black Trait will not work when Haphazard Flashes Vow is active.

Overflow system:
If you go over your CE cap by gaining CE from black flashes; you can go over the cap for a max of 10s before it's clamped back down.

TL:DR
Seems really complicated, but the black flash button now puts you in focus mode. In focus mode, you need to hit a certain amount of damage to have a chance of hitting black flash. Every time you get to a certain damage threshold, the next focus mode threshold is lower, the cooldown is lower, and black flash chances become higher.

This mod is highly configurable

Cursed Fate: Black Flash was conceptualized by TunaPogluga and coded by Weakerthanman.
Thanks weaker!

Cursed Fate: Black Flash Rework