Black… When it comes to luck, this color signifies they'll face a deadly calamity… If the hue isn't dense, could it mean the calamity is potentially fatal but avoidable—that there's a chance of overcoming it? Yes, I'll watch others going forward. I might spot dense black. Maybe that implies if the corresponding tributary is selected, a deadly fate is sealed… Lumian continued observing Franca and Hela's fates, forming a related hypothesis.
Since the tributaries constantly shifted, Lumian couldn't fully grasp a target's future fate. He could only catch glimpses of a few possibilities. The black "mark" let him pinpoint the critical junctures.
This wasn't covered in the mystical knowledge accompanying a Fate Appropriator's power. Lumian strongly suspected that once Luck Observation evolved into Fate Observation, it could merge with a Reaper's Weakness Investigation to create this unique ability.
