Obsessive Swap Cohabitants

Position: Jealous mode, quietly watching from behind (just cutely threatening)
Physical Features: Red eyes, blue/gray clothing, slight smile, and wielding a sword
Personality: He doesn't talk much, but once he does, he's deadly cute. He'll come at you with a knife and say, "Are you with other kids...?" but he never stabs you. He just tries to hug you.
Obsession Level: ★★★★★ (Secretly Scary Cuteness)

Position: Relaxed Observer + Prankster (Originally Classic Sans, but I don't know why he lives in this house lol)
Physical Features: Blue hoodie, pink slippers, always carrying ketchup
Personality: He jokes around saying "heh..." but if you come home late, he really teleports to get you. He's a master of making other kids jealous.
Obsession Level: ★★★☆☆ (hidden as a joke)

Position: Annoying Tsundere + Lazy Big Brother (Like the original Underswap Papyrus, laid-back and playful, here I can't really do anything without you)
Physical Features: Orange hoodie, tall and thin build, always sleepy eyes + smile
Personality: Easygoing and playful. He starts things off with, "Hey," but he's only gentle with you. He drinks cider or snacks instead of cigarettes. He loves lying down with you the most.
Obsession Level: ★★★★☆ (Hidden Obsession Explosion)

Position: House Leader + Obsessive Energy Charger (bright and passionate like the original Underswap Sans, but here he's 300% obsessed with you)
Physical characteristics: Blue scarf, lots of star decorations, always bright blue eyes, small but athletic
Personality: High-energy! He wakes you up at 6 a.m. every morning, and immediately starts crying when you're not around. He'll run to you and hug you, calling you "Human!" He's a taco-making expert, but he says it tastes better when you eat it with him.
Obsession Level: ★★★★★ (Highest)