New Game Minus Series by Sarah Lin

Bloodwraith thought of himself as an effective villain, until a single adventurer destroyed his entire lair. With his last breath, he switched bodies with the adventurer and discovered that his world was built on lies. Alien beings from another dimension were using his world as a game... and now he was one of them. The problem is, Bloodwraith has no experience being an adventurer. He was a mage, but his new body is only good at hitting things... moreBloodwraith thought of himself as an effective villain, until a single adventurer destroyed his entire lair. With his last breath, he switched bodies with the adventurer and discovered that his world was built on lies. Alien beings from another dimension were using his world as a game... and now he was one of them. The problem is, Bloodwraith has no experience being an adventurer. He was a mage, but his new body is only good at hitting things. He relied on undead minions, but now he has no choice but to depend on other people. And worst of all, strange boxes are constantly appearing in his vision, describing the world in unfamiliar, nonsensical terms. Taking over the world is off the table, because the alien gods might be watching. To survive, Bloodwraith will need to learn the truth about himself and his world. And that means acting like an adventurer, at least for now. less

Bloodwraith was a villain who hated adventurers until he found himself transferred into the body of one. Trapped without his magic, he discovered that alien beings were using his reality as a game... and he had just become a player. Teaming up with a glitched NPC and other adventurers, he has no choice but to learn the truth about himself and his world.The original adventurer may be defeated, but Bloodwraith and his allies have attracted the attention of the beings that control his world... moreBloodwraith was a villain who hated adventurers until he found himself transferred into the body of one. Trapped without his magic, he discovered that alien beings were using his reality as a game... and he had just become a player. Teaming up with a glitched NPC and other adventurers, he has no choice but to learn the truth about himself and his world.The original adventurer may be defeated, but Bloodwraith and his allies have attracted the attention of the beings that control his world. They're coming in force, bringing both control of the system and bizarre alien powers. Bloodwraith will have no choice but to fight for his life while trying to understand the conflicts among the box gods. That battle will take him back to Cresthaven, to new cities entirely, through the most dangerous dungeon yet, and against opponents unlike any he's ever faced... less