Ariari

Ariari is the one who re-surfaced the continent of Mu and also invented all types a technology that uses the power of the miracles. Ariari is the only slave knight that talks to Ryuu very casually, and also is the one in charge of the huge infodump. She is also the one who openly expresses her worries about the fate of Mu kingdom in the current king's hands, and if anything I agree with her.

As one of the the most famous Royal Slave Knights, she is known to the Maya Union as the "Genius of Cruelty" alias "Death Torrent".
She speaks frankly to Ryuu, likes jokes and pranks but openly shouts at him whenever she feels uneasy . She's in charge of developing weapons and remodelling the palace. She's in the middle of incorporating the Narayana series' power of miracles in her research and development. The technologies "Regeneration" and "Noah's Ark" were the result of this research/development. She can also use the miracle called "Cherry Blossom's record" for various things like performing medical examination and treating the King.

Maya Union assassination target with the priority number of 5