The Arcane skill that was developed by Nova's grandfather was not a complete skill. Since it was not given by the system, but rather forcibly developed by injecting an excessive amount of mana into Nova as a child, she couldn't use the skill for long periods of time without seriously damaging her body. The drug Aquinox that Nova took was what allowed her to use the Arcane skill without taking too much damage to her body, and if not for that drug, then the skill would have killed her a long time ago. That was why she wasn't able to last long in her fight against the Lumineers that came to this world.
Nova hadn't had access to the drug ever since she left the Silverfrost household, so she has only been using her regular skills to hunt in dungeons. So when she suddenly activated the skill again to fight against the Lumineers, her body couldn't take the strain, and she passed out almost immediately.
