Bukkororii is a young man from the Crimson Demon Village, a community known for its eccentric and dramatic residents. He is the son of the village's most prominent shoemaker, a trade he is expected to inherit, though he shows little genuine interest in the work. Physically, he has messy, chin-length light-black hair and the crimson red eyes common to his clan, which glow intensely when he experiences strong emotions. His typical attire consists of a long-sleeved shirt, a brown waistcoat, an orange cravat, a knee-length brown cape, long blue pants, a waist apron, and fingerless gloves.

In terms of personality, Bukkororii is a quintessential member of the Crimson Demons, possessing a pronounced chuunibyou tendency to act out dramatic fantasies. He frequently introduces himself in an overblown manner and strikes cringeworthy poses. More significantly, he is a NEET, a person not in employment, education, or training. He avoids taking over his father's business, preferring to laze around his home or wander the village under the pretense of "patrolling," always claiming he is saving his true power for when the world truly needs it. This laziness is compounded by a notable lack of social skills and tact, leading him to make inappropriate or creepy remarks. When embarrassed or frustrated, he tends to shut himself inside his home for days in a state of depression.

His primary motivation, aside from avoiding work, is his infatuation with Soketto, a fortune teller considered the most beautiful girl in the village. This obsession manifests as stalking; he uses his abundant free time to investigate her daily routine and concoct bizarre, often pathetic, schemes to get closer to her. One such plan involved digging a deep pit for her to fall into so he could heroically rescue her, though he ended up trapped in the pit himself. He also uses his magic, such as the invisibility spell Light of Reflection, to spy on her, though she is typically aware of his presence. His awkward attempts to win her affection, including a disastrous effort to hunt a One-Punch Bear for its liver to pay for her fortune-telling services, consistently backfire, often resulting in him accidentally injuring her with his own powerful magic. In a pivotal moment, Soketto agreed to divine his future lover for free, but when her crystal ball showed no one, Bukkororii fled in despair, unaware that fortune tellers cannot predict events concerning themselves, leaving a hint of potential mutual feeling.

Bukkororii's role in the story is primarily that of a comedic side character within the Crimson Demon Village. He is a neighbor to Megumin, having known her since childhood and viewing her as a little sister. He also interacts with Yunyun, often coercing her and Megumin into helping him with his romantic schemes by bribing them with food. Despite his laziness, he is not entirely useless. Along with other village layabouts, he formed a vigilante group he dramatically named the "Anti-Devil King Army Guerrilla Unit" or "Red-Eye Dead Slayers" to justify their idleness. However, when the village is genuinely threatened, he does participate in its defense. He uses his advanced magic to help fend off attacks from the Devil King's army and even aids Kazuma's party when they are in peril, rescuing them from enemy soldiers and teleporting them to the village. He shares a particular camaraderie with Kazuma, as the two bond over their shared indolent lifestyles.

While Bukkororii does not undergo a dramatic personal transformation, his circumstances shift slightly over time. His feelings for Soketto remain unresolved, and his behavior continues to exasperate her, though she does not seem to truly despise him. He becomes a familiar and reliable, if eccentric, presence in the village's defense force, stepping up when actual danger arrives. His relationship with Megumin's younger sister, Komekko, also develops, as he begins approaching her with food, much to Megumin's concern.

As a member of the Crimson Demon clan, Bukkororii is an Arch Wizard of considerable power, having mastered advanced magic from a young age. His magical repertoire is destructive and potent, but because he skipped learning basic and intermediate spells, he has difficulty restraining the power of his own attacks. Among his known spells are Inferno, which summons enormous flames; Tornado, which creates a devastating whirlwind; Burning Flash, a tornado of lightning; and Light of Saber, a beam of light that can cleanly slice through targets like a One-Punch Bear. He also possesses the utility spell Teleport, which can transport himself and up to three others to one of three pre-marked locations; his chosen spots are the village entrance, the doorway of Soketto's home, and the library of Red Prison.