An ability detector finds Rank S Lightning Mastery and they choose to replicate it. Physical contact triggers a painful transfer; numbness and tingling spike as replication reaches 100% and succeeds. They obtain an Enhanced Rank S Lightning Mastery and realize it's stronger than hers. Told it upgrades by absorbing electricity or Felbeast Cores—cores won't be available until the apocalypse—they immediately absorb ambient power, pushing Lightning Mastery from Lv.1 to Lv.5. Now more powerful, they still face a clear problem: Felbeast Cores are locked behind the apocalypse, blocking full upgrade.