If I had to guess.
- Sprout Traumerei: 100, probably could go up to ~120-130 if he absorbed Leviathan + all the Shinheuh of the BHs for theoretical max power.
- Urek: With Shinsu alone, probably like ~180. Combining Light with Shinsu should push him much higher, though. Not confident to give him any numbers.
- Gustang: As far as he showed at the Sprout using his own powers, probably like ~60-70. With Blossom's flame, like ~130-140. I don't think we saw the full extent of his own powers, though. When he does showcase them, I expect him to be over 100 even without the flame.
- Luslec: As far as he showed, like ~30-40. For theoretical full power, probably like 55-70. Feels like he could win against Urek if he went all-out, despite knowing Urek was also holding back, but doesn't have a clue how strong Urek really is. Personally, I put him at 30-40% of Shinsu Urek for now (~20% judging only by what he showcased). Urek doesn't really seem to view him on the same lvl as the FHs, and Traumerei effortlessly broke through his Bright Charge with Disconnection, never bothering to acknowledge his presence. Gustang seemed to give him a bit of an acknowledgment, calling him an "unwelcome guest", so he's probably not fodder (maybe a threat to an exhausted FH, but not comparable to a fully powered one IMO).
- Dumas/Rob/Astronaut/Ratna: ~10. They're clearly far below TTs. Adori could casually one-shot Proust, who was depicted as difficult to get past by Robadon. Robadon and Dumas are probably comparable given how they're the greatest warriors of their families, and how they acknowledged each other when they met. Astronaut effortlessly bypassed Gran Abuelo's defenses, while Ratna was superior to a version of Yama that was even stronger than the one who broke Proust's barrier. Feels like both would belong here.
- Kirin: ~8. Was always depicted as a solid cut beneath Robadon in their direct fights, but could still somewhat hold the ground. Should probably be close to the other FH wannabes, but doesn't feel quite as impressive as them so far.
- Boss: Should be above Regents for the simple reason his subordinates appear to be Regent-level, but I'm not confident putting him on the same tier as Luslec or TTs yet. Boss admitted Urek would have wiped them out if they retreated a second later, while Luslec simply had a much better portrayal. ~20-40 for now. I wouldn't be surprised if he ended up as TT lvl, but SIU hasn't given him much to work with yet.
- Tiara: She fluctuates massively. If she's able to use the pen properly, I think she could have a decent shot against a Regent (so ~8-10). Without it, she's clearly not comparable at all, since Yuri was depicted as being stronger than her. I don't think she's beating any Regent, because they'll simply press and overwhelm her to the point that she won't be able to write anything relevant. Maybe like ~5 overall?
- Current Yama: Base Yama probably ~3-4, while Transformed Yama ~6-8. He's a bit of a headache to rank, because on one hand, his Base form already accomplished something Robadon failed to do twice (break Proust's barrier). On the other hand, his transformed state seemed below Ratna Gra, who's a FH wannabe like Kirin inside Revolution (and probably not much stronger than him?).
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