Renkin Arthur is one of six champions chosen by the sacred sword Excalibur, tasked with correcting historical distortions caused by rampant Arthurs. She serves as an alchemist in training, wielding an oversized mallet as her primary weapon.

Physically short with chest-length blonde hair and striking orange eyes, her childlike appearance belies a sharp intellect and bold explorer's spirit during missions.

Interpersonally, she exhibits marked shyness regarding physical intimacy. She blushed and grew tearful when embraced by Dancho Arthur after a rescue, reacted nervously to Dancho's post-bath flirting, and employed her hand as improvised cover for Dancho's breasts at a seaside resort, flustering under Dancho's teasing. Similarly, being called "Big sis" and hugged by Arthur Sunshine brought simultaneous happiness and shyness.

Her relationship with fairy companion Bodach shows complexity; bound together, she flushed crimson upon discovering Bodach's dream about her. Beyond combat, she engages in matchmaking, albeit nervously, specifically "shipping" male partners Tekken and Kakka.

A significant trait is her resistance to perceived infantilization. She became visibly upset after being treated like a child, later proving her capability by independently handling subsequent trouble, indicating a desire for recognition of her maturity and competence despite her stature.