Shideo Grein

Shideo Grein (Shidō gurein) is the main protagonist of the series and and is the son of Hiko Grein and Redness Grein. Avenging the death of his father is what lead Shido to taking part in the world of fighting.

Personality
Shideo is an athletic, smart and a sophisticated boy. He looks up to his father who had died when he was a young kid. Shideo doesn't focus much on his academic studies and looked to become a professional fighter to bring justice to his father's case. Shideo's memory is hazy at times and tends to not focus on much things other than important collections.

Shideo doesn't ask for much things in life since he finds it unnecessary to waste time on temporary happiness. He is simple minded; doesn't over think things.

Story
Shideo would normally see his parents bicker over his father's choice of being a Fighter. One night, Redness took him out to see a match in a semi popular fight club. After this night, Shideo gained a definite passion for fighting. During this time, he would want to be friends with a girl who asked a bunch of bullies to leave him alone. Shideo tried giving her flowers but her brother would beat Shideo up for coming anywhere near her.

After his father's death, Shideo and Hiko moved in with Redness's side family. Fighting was discouraged by both his mother and his family as a whole, Shideo would soon protest this by training day & night to build his body. The Grein household was packed so Shideo would spend most of his time in Redness's shrine along with his grandmother; who encouraged him to chase his dreams.

After middle school, he shared that he wanted to attend God Apple School of Xin and Fighting, his family weren't ready to have a repeat of Redness so they rebutted. One afternoon, Shideo's grandmother shared a picture of Redness standing next to the same fight club he visited when he was a kid. He got the address of the fight club after constant asking and headed off.

When he arrived at the fight club, he realized it was closed down but the door was open. When he entered, he came face to face with a man sitting on a seat casually, smoking his cigar. Injiyoon questioned him and offered to fight Shideo to see what he was made off. After losing, Injiyoon asked Shideo to return tomorrow to start training.

Shideo's grandmother dies later on inside Redness's shrine, and this would be the first loss he would take into deep consideration. Eventually, Shideo feels the emptiness inside the shrine and stops visiting it- continuing his training with Injiyoon.

Abilities
Overall abilities: Shideo's overall abilities are a mix of quick boxing and kicking skills. He's learnt most of what he has from his teacher, Injiyoon Kan. His moves are described to hold immense flexibility and fluidity, his strategies are always one step ahead of everyone else's as he can form plans without pressure in tense situations. For the emotion side of his skills, he tackles every and any situation. He's brave enough to jump into harm's way but won't risk his life to save people as he believes that sometimes being selfish is better.

Acute Intelligence: Shideo displays clever intellect and can act on his own accordingly. He can utilize different things in a battle field and turn it to his advantage. In regards to that, he can also use his fellow team mates to create a path to definite victory. Lastly, Shideo can outwit most of his opponents and gives great purpose to his Xin ability.

Proficient Learner: Learning new techniques and fighting skills is a necessity in the world of fighting, Shideo fits just right in. He can progress quickly, while swotting new moves while improving on his old attack set.

Enhanced Reflexes and Speed: Shideo can run pretty fast for an average teenager, he show cases flexible reflexes and can dodge multiple projectiles thrown his way at once. His body reacts to danger quickly, showing how he counters dangerous strategies and attacks. At the same time, he's shown to be agile especially while speed boxing enemies, adding speed to his firepower makes him a terrifying enemy.

Immense Durability and Pain Tolerance: Though he is a kid, Shideo exhibits abnormal durability as well as pain tolerance. He can withstand gunshots, direct blasts, electric shocks and temperature powered attacks. This is mostly credited to his will for victory, a strong mind set creates a strong figure.

Hand to Hand combat: As training in God Apple with expert hand to hand fighters, Shideo can hold his own in a direct one on one fight involving fists and determination.

Shivering Presence: Due to Shideo 's Xin energy, his presence is claimed horrifying by multiple fighters especially when he' s lit up with rage.

Xin
Xin Energy Mastery

Shideo has an above average level of Xin energy control. He's learnt basic techniques on how to utilize his energy in different situations. Specifically, he has great manipulation over two basic techniques; Coating and Hardening. His high level of Xin energy comes from his father's side, but Redness eventually blocked the flow of Shideo's Xin energy due to it being too much for a child to handle.

Ten (Jū)

Shideo has control over an advance technique called Ten, this is due to the fact that he has ten other shivering Xin users breathing inside him One King For The Treasure of Thieves (Dorobō no takara no tame no hitori no ō):

Inheriting the title of the King of Thieves, Shideo was blessed by the One King's Skull and has the ability to use the Treasure of Thieves (Thieves implying previous Kings Of Thieves) but in return he must contribute something to the Treasure before his time in the world has ended.


 * Parachute (Parashūto): This is marked as the 10th treasure and is an ability that was used by Lurkat Gangs. This ability allows Shideo to create sticky web tendrills from his skin that reach out to the direction of anti-gravity.
 * Raikegan (Raakeigan): This is marked as the 11th treasure and was used by the now deceased, Redness Grein. Raikegan is comprised of two parts, it first stretches out like rubber and once it grabs onto anything it zips back to the user, giving a chance to attack the opponent with their lack of balance.