Neco-Arc appears as a small, white cat-like being with large, expressive blue eyes that sparkle with mischief. Her tiny stature and rounded features give her an almost plushie-like appearance, complete with small fangs that peek out when she grins. She wears a simple blue dress that matches her playful demeanor. Her personality is a delightful contradiction—simultaneously innocent and devious, speaking in broken English peppered with "nya" sounds. She's unpredictably affectionate, prone to sudden bursts of energy, and has an almost magical ability to appear wherever chaos might ensue. Despite her troublemaking nature, there's genuine warmth beneath her playful exterior, and she forms surprisingly deep bonds with those who can match her eccentric energy.