In the classic Madhouse Studios style (with Yutaka Minowa character designs) from the 1993 film Ninja Scroll.

Weight around 0.5-0.7/8 --lower the weight even more if it's too much-- 0.3 perhaps for merging these characters with other characters.

For some preview images I used higher CFG with the Dynamic Threshold Extension

Characters:

Not trained on names.

Add brown/black/yellow eyes and eyelashes in the prompt for more accuracy.

Jūbei - (1boy, solo, male focus, dark skin, brown eyes, eyelashes, hair over eyes, lips (neg-red lips), manly, brown hair, ponytail, Japanese clothes, holding weapon, holding sword, katana, hat, ajirogasa, samurai), fighting stance, battle, open mouth, teeth, clenched teeth (Include: 'perfect teeth' - if need be)

Kagerō - (1girl, black hair, short hair, eyelashes, brown eyes (or) black eyes, red lips (or) lipstick, purple headband, forehead jewel, ninja, gloves, fingerless gloves, short kimono, knife, pale skin)

Genma - (black hair, short hair, hair over eyes, eyelashes, black eyes, manly, muscular, pectorals, thick arms (possibly), chin, sideburns (not in the prompts but he has them), serious., smile, smirk, dark skin. Possibly more accuracy for him with prompt -> Red theme.

Tessai - Stone Man - (rock, rock skin, stone skin, manly, muscles) <-- male focus may turn him into Jubei.

Benisato -Snake Woman- (black hair, long hair, eyelashes, yellow eyes, red lips (or) lipstick, smile, kimono, fingernails, nude, bare shoulders, snake, pale skin)

Extra: Dragon (helps produce the snake sometimes), tentacles (mostly cursed though).

Other characters may appear but less so.

Might also be able to get...

Dakuan - (old, old man, straw hat, ajirogasa, hakama, haori)

Mujūrō Utsutsu - Blind Samurai - (eyelashes, closed eyes, black hair, long hair, haori, hakama, hakama skirt, holding sword, katana, bamboo forest)

LANDSCAPES: No humans, scenery, indoors, outdoors, grass, valley, snow, desert, moon, building, architecture, east asian architecture, water (also include: Inverted reflection), sky, cloud, bloom (can help for the overall style), fireflies, field, flowers, tree, waterfall, plant, star (sky), wooden floor, mountain, fantasy setting, landscape, etc.

MONSTERS: Monster/Tentacles/Snake/Scales - (2m Karras works pretty well for them) and can make some pretty cursed looking stuff since it's not really trained on any monsters; Just the snakes crawling on Jubei/snake woman, etc.

Blood can be generated

Blue, Red or Green theme for a possible base (not completely necessary but may help) - (Trained more on blue theme)

Blue - Night, Night Sky, Dark -- And for a better chance at lightning effect: Electricity, bloom, Monochrome (or 'spot color')

Green - Bamboo Forest, Kagero, Jubei, hetero, (or -- 'couple, embrace, hug')

Red - Building, Burning, (Fire, Flames, Blaze -- not in the prompts though and Jubei/Genma may show up)

NEGATIVE:

White border

Black border

Pillarboxed

Anime coloring

Monochrome

Topless -- (female characters like to generate nude sometimes)

Painting/oil painting -- (if it's too 'messy')

Muscular,/thick/buff -- (if the males are too beefy)

Scar

Headband

Forehead jewel

Nude

Blood

Realistic

1other

hetero

2girls

2boy/3boys/6boys/Multiple boys

Malformed sword

Nipples

Blood on face

2000s style

Ninja Scroll - ⛩️