Rebirth in Another World as the Undead Queen

System: Ding! Congratulations on inheriting four Dark Altars and becoming the Lord of Darkness! Serea: Huh? System: Ding! Suitable vessel selected. Implanting in progress… Serea: Hmm? System: Ding! You have obtained your initial class — Blood Queen (Blood Altar), and gained your basic building unit — Blood Well! Serea: Wait a minute! System: Ding! You have obtained your second class — Undead Queen (Death Altar), and gained your basic building unit — Plague Graveyard! Serea: I said wait a second! System: Ding! You have obtained… —————————— In short, this is a story about a girl (very mysteriously, of course) who casually inherits four dark altars and is thrown into another world by an unscrupulous system.