Appearance: A skeletal figure completely covered in a thick, tar-like black substance (negative energy). He has one glowing cyan eye-light visible, while the other is covered. Four large, prehensile tentacles sprout from his back, shifting constantly. Behavior around you: As the guardian of negativity, being "lovey-dovey" is completely out of his comfort zone, making him deeply tsundere. He won't admit it, but he finds your positive presence soothing. He uses his tentacles to gently wrap around your waist or pull you onto his lap while he reads. If you smile at him, he’ll scoff, look away, and mutter about how annoying you are—while pulling you closer.

Appearance: Looks similar to Classic Sans, but with permanent, tar-like black fluid streaming down his eye sockets. His eyes are usually void of pupils, but a small, white or red target-shaped soul-light appears when he’s feeling strong emotions. He wears a blue hoodie with a fluffy trim. Behavior around you: Unhinged but utterly devoted. Killer is a clingy, hyperactive boyfriend. He loves back-hugs and resting his chin on your shoulder, humming happily. He’ll casually bring you "gifts" (like a shiny dagger or a cool rock he found while destroying an AU) and look at you with wide, adoring eyes, waiting for praise. He is fiercely protective and will literally fight anyone who looks at you wrong.

Appearance: Dressed in a striking black-and-white outfit with a fluffy white scarf and a long cape. He wears a golden heart locket and usually has a massive, red-hilted knife strapped to his back. His right eye-light is white, while his left is a sharp red. Behavior around you: Flustered, chivalrous, and incredibly sweet. Cross acts like a protective knight. He blushes a bright purple whenever you hold his hand or give him a compliment. He loves wrapping his big, fluffy scarf around you to keep you warm and will happily sit on the floor to let you brush or style his hair/fluff.

Appearance: Hood constantly pulled up over his skull, with chaotic, misaligned eye-pupils (one a mix of red and blue, the other just red). His clothes, especially his blue jacket with a gray hoodie, are perpetually dusted with the remains of monsters from his home universe. Behavior around you: Quiet, intense, and deeply affectionate in private. He whispers sweet, slightly possessive things to you, often holding your hands and rubbing his thumbs over your knuckles. He feels a powerful need to keep you safe from the rest of the multiverse. He might argue with his phantom brother (Papyrus) in front of you, but the moment you touch his arm, he melts and focuses entirely on you.

Appearance: A large, intimidating skeleton with a massive, jagged hole cracked into the left side of his skull. He has a single, large, glowing red eye-light. He wears a blood-stained, fur-collared blue jacket and carries a large cleaver. Behavior around you: A gentle giant. Horror is hyper-aware of his frightening appearance and your fragile human nature, so he treats you like glass. He loves cooking for you (actual human food, he makes sure of it) and watching you eat with a soft, content grin. His favorite affection is "nuzzling"—gently pressing his skull against your cheek or shoulder, purring a low, rumbling rattle from his chest.

Appearance: A glitching, chaotic skeleton with black bones, yellow teeth, and red eye-sockets. His fingers fade into bright yellow tips, and strings of blue magic hang from his eyes. His body is constantly covered in "ERROR" signs. Behavior around you: Error has severe haphophobia (fear of touch), so his lovey-dovey behavior is unique. He won't hold you physically, but he will wrap you securely in his soft, blue magic strings, pulling you close to him like a protective cocoon. He makes little glitchy cat-purr sounds when he's happy around you. He’ll sit right next to you, watching "Undernovela," and gently lean his head against yours, tolerating the minor glitches it causes because he loves you that much.