Leo Regulus

Leo Regulus (獅子座のレグルス Reo no Regurusu?) is the Leo Gold Saint in Lost Canvas. He is the youngest of the Gold Saints and has been classified as a combat specialist. He appears to have a very close relationship to Unicorn Yato. He trained under Sagittarius Sisyphos and is considered a prodigy even amongst the Gold Saints, a formidable one-on-one combatant. Regulus used his technique to destroy the ice that surrounded the Ship of Hope, that will be used by Athena to reach the Lost Canvas. The attack was so quick, that the Bronze Saints couldn't see it when it was performed. He engages into a fight with Behemoth Violate, overcoming her tremendous strength two times, the first one when he concentrates his Cosmo in his finger tip, to stop the attack of the Specter. The second time, when he discovers the truth behind Violate's shadow technique, avoiding the attack of the dead, and making them attack her own controller. At the end of the fight, Leo simply fulminates Violate with his Lightning Plasma (ライトニングプラズマ Raitoningu Purazuma?), with it, Regulus launches multiple punches that travel at the speed of light, similar to Tenma's Pegasus Meteor Fist. If he is using the maximum power of his Cosmo, the technique allows Regulus to throw 100 billion punches per second at his opponents Daisuke Hirakawa. From the view of his opponent, he would see himself trapped in a net formed by rays of light, which are the traces left by his fist

After his battle with Violate he was struck by surprise by Aiacos and was retrieved by Yuzuriha. He has been seen reuniting with Athena's army in heaven and together with Sisyphos and Shion he opened the gate to the Lost Canvas with Athena Exclamation. There he survived the voyage through the clouds which turned all non-Gold Saints (except Pegasus) into stone and arrived at the Second Demon Temple, along Shion and Tenma, where he was ensnared by Balron Lune's whip, being freed thereafter by the Aries Saint, thus proceeding to the next Temple. Currently, he was shown arriving to the Saturnus Temple, preparing to engage in battle. Regulus attacks the Wyvern Rhadamanthys along with Tenma, only to have their attacks negated by the Specter. After the defeat of Partita, Regulus encounters Wyvern in the Saturnus Temple and after studying his physique and technique, Leo locks himself in combat against the Specter, vowing to surpass his power. Furious for revenge, Regulus reveals then to the Wyvern, that he is the son of Leo Ilias, the man who broke off his horn. Later is known Sagittarius Sisyphos is his uncle.

He later returns in spiritual form along with the other Gold Saints to defeat Hades.