Regulus Corneas is a Sin Archbishop of the Witch Cult, representing greed.
Regulus Corneas possesses the Authority of Greed. The Authority itself is split into two main abilities–Stillness of an Object's Time and Lion's Heart:
Stillness of an Object's Time: The so-called Stillness of an Object's Time was Regulus' mainly offensive ability, named by Subaru. Regulus could stop the time of anything he was wearing, touching, or even his breath, which in turn stopped the object's or thing's interference from the outside world, only allowing its interference outwards and even granting Regulus the ability to freely manipulate the objects' shape. Small objects imbued with Stillness of an Object's Time could be used either as a form of platform which allowed Regulus to freely traverse on it, or be utilized as objects of imminent death and destruction as they created devastating and destructive attacks when used with malicious intent.
Lion's Heart: Lion's Heart–Regulus' purely defensive ability–allowed him to freeze his heart's time, stopping his heartbeat and granting himself a temporary state of invincibility. While this power was active, Regulus was completely cut off from the world's flow of time. He did not have any need for eating, drinking or even breathing and his body did not age a single second, nor did it perform even the most basic of human body functions such as sweating or excreting bodily wastes. He could even ignore every physical law he wished, traveling at inhuman speeds making it seem like he's teleporting around the place, ignoring gravity and scaling multi-story buildings by just lightly pushing himself off the ground. According to Reinhard, he did not possess a heartbeat and had a corpse-like body temperature. Lion's Heart acted as his ultimate defensive ability as it allowed him to simply ignore any and every form of damage dealt to his body. However, this ability did have a downside to it, in form of a time limit. Whenever Regulus used this ability for more than five seconds at a time, he began to experience almost unbearably excruciating pain, which prompted him to quickly deactivate it. If he would continue with the usage of it, without taking pauses, Regulus would die from heart failure. He had noted that he could, in theory, push the limit to around ten seconds, but the pain and the fear of dying were too much for him to handle. In order to circumvent the handicap given to him in form of the five second rule, Regulus gave away his Lion's Heart to the subjects of his Kingdom, or in other words, to any woman who he considered to be his wife. By doing so, he would effectively get rid of the timer and the necessity to manually turn the ability on and off, as by merging his heart with his wives' hearts, their heartbeat would keep his ability activated, and it would last until his wife's death. In order to circumvent that potential drawback, Regulus accumulated over two hundred wives in his over-a-century long life. By doing so, the risk of all his wives dying and being exposed to the strains of Lion's Heart were practically zilch, as no one would ever connect his wives with his Authority. Naturally, as the wives' Lion's Heart was only a pseudo-heart, they didn't bore any consequences, let alone were they even aware of harboring it inside of them. The range of the paired up Lion's Heart is unknown.
He later drowns and is killed during the battle in Priestella in Arc 5 by a joint force consisting of Reinhard van Astrea, Natsuki Subaru and Emilia.
