Shu Ouma is one of the main protagonists of Guilty Crown, whose right hand holds a special power called the Power of Kings, given to him by the Void Genome. He attends Tennouzu First High School in class 2-A and is a member of the modern motion picture research club.
He is usually seen wearing his school uniform. He has brown hair with a light streak on the left side and brown eyes. For his time with the Undertakers, he wore their standard uniform.
Shu was an unsociable 17 year old who tended to stay out of peoples way, forming quasi-friendships with others, but nothing more significant. However, this changes when he meets a girl named Inori Yuzuriha. From that moment on, he gains the responsibility of one with "The Power of Kings," and he must learn to overcome his own weaknesses and form lasting bonds with his friends and allies. During later episodes Shu has indeed begun to evole into a much more brave and sociable person, this is even noticed by Hare. However, his will is shaken at times as seen frequently throughout the series. He thinks very lowly of himself, in the beginning thinking he should better than his current personality. Very early in the series, Shu gain feelings for Inori, which many people easily see and attempt to use in their favor. He is very jealous when any male gets too close to Inori, and is heartbroken when she has to leave in episode 10.
At the start of the series Shu's only noteworthy ability are his observational skills and intelligence of which he even received a slight praise by Gai. Since joining the Funeral Parlor, he tried to learn hand-to-hand combat and weapons use by Ayase and other members, but has never shown any skill at this, relying more on his use of Voids.
Shu's main ability stems from the Void Genome, refered to by many as the "Power of the Kings". With this power Shu can draw out a person's Void: an object that is refered as a person's heart and ideas taken form. This ability is highly versatile, as each Void is unique to each person and have several different effects that can be used to deal with almost any situation. In order to use this power, Shu must look directly into the person's eyes as he draws out the Void which causes the person to lose consciousness. Later he showed the ability to combine Voids to create more powerful weapons as shown by combining Inori's and Kido's Voids though it's unknown if he can do this with any Void.
One characteristic of the Void Genome is that when a Void is drawn, Shu can also generate blue-energy disks that can be used as shields or as stepping stones to reach higher grounds. This ability seems available whenever he draws any Void.
His most powerful and used Void is Inori's, a large and powerful sword that he can wield effortlessly and can easily cut through a group of Endlaves. He can also this to fire a thin metallic-like energy wave from the sword that can cut through most solid objects. Using this Void also appears to enhance Shu's physical abilities greatly, allowing him to jump and move at great speeds.
After Mana's destruction, Shu's powers underwent a change, as individuals no longer collapse from having their Voids drawn out, and can even wield them like Shu.
The Genome itself is apparently bound to the user's right hand, as this is the hand where the mark of the kings is and the hand Shu uses to draw out the Voids. In episode 17, Gai severs Shu's right arm and steals the Genome, which binds itself to Gai's right arm.