📌 Key Observations
Linear Growth: The HP boost appears to increase linearly with each chapter, with Kris' HP growing by approximately 30 per chapter.
Multiplier Increase: The multiplier also increases with each chapter, reflecting the escalating challenges in the Dark World.
Character Variations: Other characters like Susie and Noelle experience similar boosts, though their exact multipliers may vary slightly based on their base HP and progression.
Susie[1] - 30 - ×3.8 - ×5.5 - ×7.5 - ×9.5 - Slightly lower than Kris, but similar rise
Noelle[2] - 25 - ×4.2 - ×5.8 - ×7.8 - ×10 - Close to Kris, slightly different scaling
Roaring Knight[3] - 40 - ×3.5 - ×5 - ×6.5 - ×8 - Lower multipliers, reflecting stronger base HP
📊 Dark World HP Boost Multipliers by Chapter
Character - Base HP - Dark World HP - Multiplier
Chapter 1
Kris - 20 - 90 - ×4.5
Susie - 30 - 114 - x3.8
Noelle - 25 - 105 - x4.2
Roaring Knight - 40 - 140 - x3.5
Chapter 2
Kris - 20 - 120 - ×6
Susie - 30 - 165 - x5.5
Noelle - 25 - 145 - x5.8
Roaring Knight - 40 - 200 - x5
Chapter 3
3 - Kris - 20 - 160 - ×8
Susie - 30 - 225 - x7.5
Noelle - 25 - 195 - x7.8
Roaring Knight - 40 - 260 - x6.5
Chapter 4
4 - Kris - 20 - 210 - ×10.5
Susie - 30 - 285 - x9.5
Noelle - 25 - 250 - x10
Roaring Knight - 40 - 320 - x8
Chapter 5
5 - Kris - 20 - 270 - ×13.5
Susie - 30 - 345 - x11.5
Noelle - 25 - 308 - x12.3
Roaring Knight - 40 - 380 - x9.5
Chapter 6
6 - Kris - 20 - 340 - ×17
Susie - 30 - 405 - x13.5
Noelle - 25 - 365 - x14.6
Roaring Knight - 40 - 440 - x11
Chapter 7
7 - Kris - 20 - 420 - ×21
Susie - 30 - 465 - x15.5
Noelle - 25 - 425 - x17
Roaring Knight - 40 - 500 - x12.5
UltSans
Chapter - HP Multiplier[4]Â - AT Multiplier[5]Â - DF Multiplier[6] - MG Multiplier[7]
Boosted HP - Boosted AT - Boosted DF - Boosted MG
1 - ×2.0 - ×1.0 - ×1.0 - ×1.0
 - -Â
2 - ×2.5 - ×1.0 - ×1.1 - ×1.0
 - -Â
3 - ×3.0 - ×1.0 - ×1.2 - ×1.1
 - -Â
4 - ×4.0 - ×1.0 - ×1.3 - ×1.2
 - -Â
5 - x5 - x1.0 - x1.4 - x1.3
 - -Â
6 - x6.5 - x1.0 - x1.5 - x1.4
 - -Â
7 - x8 - x1.0 - x1.6 - x1.5
 - -Â
Conclussion:
Ralsei does not get a boost, as is a darkner, and in Chapters 1 and 2 when enemies are defeated violently, they are increasing their Lv or L.O.V.E wihout Exp. They follow the meaning of what Lv stands for, as they are distancing themselves further from the morality line, which implies an increase oof strength as they hold less and less, seeking to kill.
Kris, Susie, Noelle, and even the "Roaring Knight"; they get boosts when are in the Dark World as are Lightners. But unlike Kris, Susie or Noelle, the "Roaring Knight" has passed more time in the Dark World, which is the responsible factor of the HP, as the Roaring Knight was set as Boss Monster. This increases anomalously the boost they receive from part of the Dark World, as slowly, instead of getting a similar lineal stronger boost in every Dark World, is progressive, and goes until the Roaring Knight reached the maximal potential boost they could have received.
Kris, Susie and Noelle, could also obtain this change, but they would have to reside more time in the Dark World as the Roaring Knight, but they would receive changes apart from their already STAT boost, as they would change physically as how they look in the Dark World, as less recognizable from how they are in the Light World.
Roaring Knight
HP 7300
AT 230
DF 0
Element: Dark/Star
Description: Enemies won't flee, and will always be SWOONED.
Weapon
Name: Nightbreeze Greatsword
Type: Greatsword
AT: +40
Desc: A massive blade infused with the Roar, capable of slicing through both armor and resolve. Grants a small speed penalty.
Armor Slot 1
Name: Echoing Plate
Type: Heavy Armor
DF: +20
Desc: A resonant chestplate that hums with leftover energy from past battles. Greatly reduces physical damage.
Armor Slot 2
Name: Darkmantle Cloak
Type: Cloak
DF: +5 MG: +5
Desc: Shadows swirl around the wearer, muffling footsteps and strengthening dark magics.
Roaring Knight as vessel:
Early-game variant: Lower Weapon AT to +20 and Armor DF to +10/+3 to fit earlier stages.
Late-game upgrade: +60 AT weapon, +35 DF plate, +10 MG cloak for a power fantasy build.
[1] +x1.7, then +x2.
[2] +x1.6, then +x2, then +x2.2. A little special situation, as the Holiday family always has been.
[3] Always +x1.5.
[4] +x0.5, then always +x1.
[5] Always the same. Is futile if does not attack physically, but always uses magic for every attack, even those who are physical attacks, but imbued in magic.
[6] Always +x0.1, as even a little more gives a big boost.
[7] +x0, then always +x0.1.