Love is all!
Io Naruko


Io 2

Io Naruko Game

Biographical Information
Kanji 鳴子硫黄
Horoscope Sagittarius
Birthday December 17
Affiliation Defense Club
School Binan High
Relatives N/A
Physical and Vital Statistics
Gender Male
Height 178cm
Eye Color Light Grey
Hair Color Pale Green
Blood Type A
Personal Status
Hobbies Financial Investment and Management
Likes Money, beef bowls
Special Abilities
Attribute Yellow · Earth
Transformation (Japanese) トドロキ王子バトラヴァ・サルファー
Transformation (Romaji) Todoroki Ouji, Batorava Sarufā
Transformation (English) Roaring Prince Battle Lover Sulphur
Anime In The Name Of Love
Manga Chapter 4
Voice Actors
Japanese Yusuke Shirai

Io Naruko (鳴子硫黄, Naruko Io) is a 2nd year at Binan High School. Despite being in high school, he makes good money trading on the FX stock exchange[1]. His life motto is "Life is all about money!"[1]. He is good friends with Ryuu, who along with being a member of the Battle Lovers, is in his graduating class[1]. They call each other "Ryuu" and "Io". It is suggested that they have romantic feelings for each other or a deep friendship that has some romantic dimensions.

As a Battle Lover, his given element is Earth, and he transforms into "Roaring Prince, Battle Lover Sulphur". (Todoroki Ouji, Battle Lover Sulphur)


Io has pale green hair that goes down to his collar and his long bangs are parted and go down over either side of his forehead. Io also has light grey eyes and is the third tallest of the Earth Defense Club.

He wears a white shirt that is presumably tucked into his pants, a black uniform blazer which he has buttoned up, a pair of long black pants, a red tie and a pair of brown shoes.

When he transforms into Roaring Prince, Battle Lover Sulphur, he wears: a traditional prince-styled top with white puffed up sleeves that have yellow, flipped up cuffs with base extensions in the form of six coat tails which have a yellow underside, a yellow bow just below his neck that has a small, yellow, heart-shaped jewel with wings, embedded into it, a frilly white undershirt that barely peaks out of his traditional prince-styled top, a pair of white silk gloves, a pair of white, knee length shorts which have yellow bordering at the base, a pair of yellow boots which have the upper part flipped down to show a white inner shoe.


He seems to be one of the more level-headed characters along with En Yufuin, as seen in the first episode when he makes a point about the monster being a bigger problem. His love for money and economics shows that he is far more aware about commerce and the business world than any of the other characters in the series.

Love Making Powers


  • His last name, "Naruko" (鳴子) is derived from a Japanese hot spring referred to as the "Naruko Onsen" which is located to the north of Miyagi Prefecture in the Tohoku region.
  • His first name "Iō" (硫黄) literally means Sulphur.
  • In Season 2/2nd TV series episode 9 Io actually takes it upon himself to hire a truck for Ryuu, for him getting lots of chocolate on Valentines Day. We get to know this because Ryuu asks him if he has extra bags. Io tells Ryuu to reimburse him later. Ryuu then presents to him a box of chocolates. Io tries to act indifferent stating he has already too many chocolates from the companies he has stocks in but blushes deeply saying he will accept Ryuu's offering. Ryuu comments that maybe he will get more chocolates than him by the end of the day. It is suggested that Io has a crush on Ryuu which is somewhat reciprocated by Ryuu.