Regulus Corneas (レグルス・コルニアス) was a Sin Archbishop of the Witch Cult, representing greed until he was defeated by Reinhard van Astrea, Natsuki Subaru and Emilia. He was one of the primary antagonists during the fifth arc of Re:Zero.
Regulus is described to have a "normal" appearance, with features that aren't handsome yet not ugly. He has a thin body along with white hair that isn't long nor short, nor arranged in a strange way. He has gold eyes and appeared to wear a blue earring on his right ear. In the Web Novel, he wears black clothes that follow the same concept, making him ordinary enough that people would forget about him soon after spotting him. However, in the light novel his clothes got changed to white, with less simple concepts.
During the wedding of the fifth Arc, he made an appearance in a more formal outfit. The respective colors of his outfit were white, gold and slightly blue, the same color scheme as his regular outfit.
Regulus is talkative, tending to describe himself as "unselfish" despite representing greed, and often goes on and on about plausible theories, though in actuality he forces his own selfishness on others and tries to justify it. If his opponents say something that goes against his opinions, he finds unreasonable faults in them, becoming angry while accusing them of "violating his rights".
Regulus used to live with his family. His father was an alcoholic but tried to be a good father, his mother who complaining about bad earnings but apologized for it occasionally, and his two brothers who were sometimes mean to him but gave him their share of their meal if he accidentally spilt his. At some point in the past, Regulus obtained the Witch Factors of Greed, and subsequently killed his entire family, then village and then everyone in the surrounding cities.
Authority of Greed (強欲の権能 Gōyoku no Ken'nō): Regulus was able to use the Authority of Greed until his Witch Factors were taken by Natsuki Subaru following his death.
- Stillness of an Object's Time (物体の時間の静止 Buttai no Jikan no Seishi): The user can stop the time of themselves or anything they're wearing, touched, or even their breath. This stops any interference from outside and only allows the user's interference outwards. This negates any attack against the user, and if the user waves their hand anything in its trajectory is cut no matter the toughness. Atmosphere released from the stillness can cause shockwaves, gravel thrown around can become inevitable shots, and it can enable the user to travel at extremely high speeds. Normally, multiple uses of this ability can be deadly as the user's own heart also stops, however it can be circumvented when combined with another of the Authority of Greed's abilities.
- Lion's Heart (獅子の心臓 Shishi no Shinzō) or Small King (小さな王 Chīsana Ō): The user merges their heart with one of the people of his kingdom, or in other words any woman that the user has confirmed to be their wife. With this, the user can use the effects of Stillness of an Object's Time as long as they wish to. As it is only a pseudo heart, even if the merge is destroyed the only aftereffect is that the user bears the burden again. Any conditions or effect area haven't been shown.
- As of a hundred years ago, Regulus had 78 wives, and as of Arc 5 he mentioned to have 291 wives in total. However, according to Sylphy, 238 of those wives were killed, leaving only 53 alive.
- Regulus, from Latin, means "Little King".
- His namesake is a reference to the star Regulus, which is the brightest star in the Leo constellation.
- Regulus was mentioned to be a young man 100 years ago
- Regulus was the first character that was able to kill Reinhard van Astrea.