this is just a summary of characters with which Luke interacted till now after getting teleported.

Brian, the lord of the mansion.

• There is not much known about Brian except that he likes taking in mages who ended up as slaves. Most of these servants work regular jobs so that they get accustomed to regular life. Their jobs range from working on the field to protecting the workers on the field to working in some workshops, dealing with customers there, to acting as an assistant under a mage. Their scope of work is quite large, and half of their salary is used to pay off debts. The rest they receive an amount as pocket money. 
• After paying off one's debt, one is free to leave or take Brian as their patron. Those who accept Brian as their patron/(swear loyalty to him) are sponsored by Brian. This goes from tuition costs of magic academies to research grants. Currently, Brian has a few master-rank mages under his wing. Master Simon is one of them.

Master Simon, Luz's teacher and one of the master mages under Brian. 

• Master Simon is a researcher whose research focuses on parasites and how to force a symbiosis onto them. His success was quite limited till now, and Luz was the only patient on whom his experiment was successful. 
• As Luz's teacher, he's responsible to teach Luz most of the mage spells and mage disciplines. But since Luz had more concerning problems, these teachings were put aside for the time being. 
• His pet and research partner, also known as, Jodoc is a parrot from an unknown species. His mental capabilities reached that of a mage. 

Jodoc, parrot and research partner of Simona and assistant teacher of Luz.

• Jodoc's species is unknown, and he almost got sold by Simon when he was still in an egg for some pocket money. 
• At the moment, he is Luz's assistant teacher, teaching him most of the theoretical basics of the magical disciplines since Master Simon doesn't want to bother with such things. 

Francis, "friend"

• Francis is one of the mages who took Master Brian's patronage after paying off his debt. The reason for that is he had no other place to leave and rather opted out into helping new servants get accustomed to the mansion life. 
• Francis was also a team leader of a 4 men's group.
• Spoiler

  two people of the 4 men group died due to an order of Luke. In the end, only Luke and Francis survived, but their friendship is strained for the time being

  [collapse]

Roommates

• These kids are nameless for the time being, as their interaction with Luz was limited since the latter ended up living elsewhere. To keep it short, these are the other boys who ended up as slaves before getting rescued by Master Brian. Their ages range between 11 to 17. As for the current time, they mostly use some of Luke's books to teach themselves magic, setting their rooms regularly in flame.