Pokémon used to be a lot more dangerous...
Since this is my first Nuzlocke, I'm going with an easy ruleset that doesn't restrict me too much, but at the same time adds a bit of tension.

Nuzlocke Rules:
  • Can only catch one legal Pokémon per sub area. After that, all other Pokémon in the sub area are illegal.
    • Allowed to choose which Pokémon to capture from the sub area's spawn table.
    • If I attempt to capture a Pokémon and it disappears, that sub area's encounter is lost.
  • If a Pokémon faints, it is permanently boxed.
  • Allowed to capture one legal Alpha, one legal Spacetime Pokemon, and one legal Outbreak Pokemon per area.
  • If the capture is required for Story or Mission progression, it is considered legal.
  • Allowed to put non-legal Pokémon in party for the sake of evolution. Not allowed to use in battle.
  • Legal Pokémon must be nicknamed at the earliest opportunity.
    • Pokémon that are to be given away will also be nicknamed.
  • Regardless of other rules, the following Legendary Pokémon are considered illegal:
    The Creation Trio, The Lake Trio, Forces of Nature, Heatran, Regigigas, Arceus
  • Dupes Clause: If you already captured a Pokémon in an evolution line previously, it doesn't count as your "first encounter".
    • You are not allowed to use the Pokémon. If you've caught all Pokémon that can be found in a sub area, tough luck.
  • Shiny Clause: Encountered Shiny Pokémon are legal and can be used.
  • Friendly Rival Clause: Fainted Pokémon in battles with Rei / Akari will not count as deaths.
  • Revives Clause: You are allowed one revive per battle where you throw Balms. You are allowed to save the revive for later.
This is a modded game. I figure it'd make things a little more interesting than the normal Nuzlocke, or at the very least make things significantly less tedious. For transparency, the list of mods can be found here.