Dungeon Overlord: My First SSS Gacha Summon Was a Yandere

One skill. One pull a day. A whole dungeon to raise from nothing. Freya wakes in an unknown world with a system in her eyes and a dungeon to her name, armed with a single power: [ Unique Skill: Gacha ] [ Summon anything in existence, from Rank G to Rank SSS — once every twenty-four hours. ] It could hand her a piece of junk. It could hand her a god. Her first pull lands an SSS. [ Aria, Demonic Maid of Knowledge — Rank SSS ] The perfect maid: devoted, brilliant, ready to answer her mistress's every wish. With one flaw. She's a yandere, and she'll let nothing come between them. Nothing, and no one. Now the real work begins. Dig, build, summon, and level up every corner of her domain, one tier at a time, turning bare stone into a dungeon worthy of the name. But Freya isn't the only Earthling in this race. Other Dungeon Lords are raising their own domains, an entire world is branding them its enemy, and beyond the walls, heroes are sharpening their blades, waiting for a single chance: to break through, and burn it all to the ground. Fortune handed her an SSS on the very first pull. She's going to need it. — Description from novelcodex.org