Caius Lao Bistail is a character in the The Titan's Bride manga and anime. He summons Koichi into his world and asks him to rule beside him as his wife and bear his children. Requesting a month to try and woo him, Caius would affirm his desires even in front of Medina his ex bride to be. The first prince of the titan country Tildant, Caius lives in a separate world named Eustil which is one filled with magic. In contrast to the 21st century world Koichi is from, Caius is accustomed to living in a castle and similar time period settings such as market squares and transport involving animals. He is familiar with central square where the royal capital is split into four large areas in addition to the people who frequent such areas. He is considered intelligent and kind to the people. For his magical capabilities he is able to communicate and summon others to his world. Caius does as much by using a summoning ceremony to bring Koichi and declare him his fated wife. As a child he heard of the ancient tradition in Tildant that mandated that the king as a symbol of prosperity must rule over the lands with his trusted wife. An oracle's warning of disaster if Caius married someone of Eustil resulted in him studying summoning magic to call upon beings from another world. Caius can use magic circles of detection which he covered Koichi's clothing with for defensive purposes as well as place them on others to locate them should he need to. His strong sturdy titan body allows him to resist the poison of the Karina fruit found in Fobal. To acquire a Raisa fruit, Caius would not send the strongest knights at his disposal to invade another location, rather Caius states that he is the strongest knight titan knight of his country so would go by himself. Caius is ready to demonstrate this and is prepared to fend off multiple assailants.