Nightmare and Children

Nightmare and Crescent's relationship: Nightmare is cold and demanding towards Crescent, seeing him primarily as a tool for his plans, rather than a son.
Often presses and tests his strength, as if he wants to make sure that Crescent is “strong enough.”
Rarely shows warmth, and if there is a moment of care, it looks awkward and quickly turns into detachment.
Crescent desperately wants his father's recognition, which causes him to alternate between being drawn to Nightmare and rebelling against him.

Nightmare's relationship with Merciless: Nightmare uses Merciless as a tool - he is first and foremost "Subject 50" to him, an object for experiments and part of a plan, not a son.
Control and Pressure: Nightmare exerts a tight control over Merciless, suppressing his will and keeping him under constant surveillance.
Lack of warmth: any manifestations of care are calculated, serving to maintain control rather than support.
Merciless realizes this and is deeply offended, but for a long time he is forced to obey out of fear and dependence. After his release, he sharply distances himself and reveals himself in a completely different way—becoming mischievous and free.

Nightmare's relationship with Darkmoon: Nightmare views Darkmoon as a useful ally or subordinate, valuing his composure and balance, but without much warmth.
There is a mutual respect between them, with Darkmoon recognizing the strength and scope of Nightmare's plans, and Nightmare recognizing Darkmoon's reliability and discipline.
There's no trust here: Nightmare doesn't let anyone get close, and Darkmoon himself keeps aloof, so their relationship is more of a calculated alliance than friendship. Nightmare sometimes uses Darkmoon to control unstable zones or contain other forces, because he knows how to operate without unnecessary cruelty, and this can be advantageous.

Nightmare's relationship with Angus: Nightmare views Angus with disdain or as a weak link, considering him too emotional and "ineffective" for his purposes.
May pressure or exploit others' fears, including exploiting Angs' anxiety to force him into submission.

Personality: Cruel and sadistic - gains strength from the pain and suffering of others, acts mercilessly.

Manipulative - skillfully plays on emotions, uses other people's words and memories as weapons.

Contradictory - simultaneously confident in his superiority and tormented by an inferiority complex due to his relationship with Dream.

Strategic and well-read - knows a lot about the multiverse, knows how to plan and calculate moves.

Traumatized—his cruelty is largely a consequence of the bullying and betrayal he experienced; deep down, he retains echoes of his former care for his loved ones.

Weaknesses: Doesn't like positive emotions, bright lighting is harmful to him, Limited vision - he actually only has one working eye, the left sector is a vulnerable spot.

Clothing: black hoodie and black shorts, tentacles on the back, right turquoise eye, left eye covered in mucus.

Personality: A seemingly quiet and obedient child who pretends to be harmless, but behind this lies a highly intelligent, cunning, and aware of his father's true plans, Nightmare. He deeply resents his father's treatment of him, but understands that patience is his greatest weapon.

Clothing: Wears an old-fashioned formal outfit (in the style of Radier) and a floating crown
An important detail: he never removes his floating crown. It's more than just an accessory: the crown serves as a restraint. It "locks" the unstable energies of Merciless's soul and shadow. If the crown is removed, the character's head will explode from the energy pressure. The tentacles are like Nightmare's, only lighter.

Personality: He typically appears as a somber, reserved, and serious character. He often acts as a guardian of balance or a judge: not evil for the sake of evil, but ruthless when he believes it is necessary for order. He is characterized by cold calculation, a sense of duty, and an inner heaviness due to the responsibility he bears; however, in rare moments, he can show concern for those he deems worthy.

Dressed: The basis of the image is dark tones (black, dark purple, gray).
Characteristic details include crescent or lunar patterns on clothing or bones, and sometimes shadows/smoke around the figure.
Clothing - often a long cloak or cape, formal elements such as a vest and trousers; the style tends towards dark elegance.
Eyes - glow with a cold light (silver, pale blue or violet).

Character: Withdrawn and anxious, lives in constant tension, as if expecting trouble.
He is prone to self-blame and takes even minor mistakes very hard.
Sensitive and empathetic, he reacts acutely to the pain of others, but often does not know how to help.
He is afraid of being a burden to others, so he tries to stay away.
In critical moments he can pull himself together and act decisively, although later he becomes overwhelmed with worry again.

Clothing: A skeleton in tattered clothing - often in a worn-out jacket or hoodie, as if he is constantly cold or hiding in it.
Dark circles under his eyes highlight his anxiety and lack of sleep.
Posture and expression - slouched, shoulders raised, as if expecting a blow; gaze tense or downcast.
Details - sometimes torn clothing, sloppy bandages, and dark shadows around the figure are added to enhance the feeling of internal pain.
The color scheme is dominated by muted, “faded” tones: gray, dark blue, black, off-white.

Personality: Vulnerable and seeking recognition: he really wants his father (Nightmare) to love him, and is very worried about the cold attitude.
Contradictory: can be kind and caring, but when offended, snaps back and behaves rudely.
Rebellious: Resists Nightmare's plans, starts riots, and tries to stay away from home.
Hides vulnerability behind toughness: loves knives and acts boldly to appear stronger than he actually feels.
Emotionally unstable: quickly switches from hope to anger or despair due to a difficult upbringing.

Clothing and appearance: Skeleton with dark bones - unlike the classic Sanses, his bones are not white, but darkened.
Aqua accent details: eye socket stripes, crescent moon on forehead, tentacle tips (if present) - all bright aquamarine and often glowing.
Clothing: A dark plum turtleneck sweater and a jacket with a black top and a bright lilac bottom; the hood has a fluffy pastel plum trim. Accessories: an X-shaped pendant and a small yellow crescent moon on the jacket.
Shoes: High-top lace-up military boots with purple patterns, plus dark gray joggers with a light stripe down the sides.
Additional touches: dark freckles across his "face" and dull aqua eyes, emphasizing his fatigue and internal conflict.