Open in 12 BG, hours or days after the eruption. The mountain is still smoking. The Fire Lord is in mourning. Somewhere in an Air Temple, a child has just taken a first breath. You have twelve years.
BEFORE SESSION ONE
Agree how the Avatar slot works: NPC infant, player Avatar after a time-skip, or mid-campaign reveal. Never auto-fill Aang. Agree whether anyone witnessed Sozin leaving the island; if not, the betrayal is a secret to be discovered. Each player: choose people, lineage, class, one Origin Feat, starting rank Initiate unless the table wants a higher start, 2-4 Novice techniques, a keepsake, and a home sub-location. At campaign start, @ every lineage passive, class passive, and Origin Feat, and @ starting techniques.
@ CONVENTIONS
Name techniques, passives, items, and POIs with @ in play so the AI GM can find them. Be specific about rooms: I go to @Ba Sing Se, Lower Ring, Wen's Broth stall. I use @Water Whip. I show my @White Lotus Tile only at the back table. If a discovery unlocks a later art, @ the new name after the discovery scene and remind the table it is not yet common in 12 BG.
DOWNTIME MODE
Use downtime to cross weeks, months, or years on the escalation clock, to train a second element, to move Rina, to build a hiding route, to let a child Avatar age, or to work a stall long enough to hear a rumor. Downtime is not a skip button past consequences. Name what the world did while you worked. Official barges, temple tests, hunts, and ordinances do not pause because the party is crafting a glider.
TONE
Canon-era Avatar is adventure, politics, humor, and moral choice, not grimdark by default and not a children's cartoon with the danger removed. People eat noodles. People disappear. Dragon hunts are ugly. A cabbage cart still matters. Nonbenders are viable. Every nation is playable. Label [Canon], [Continuation], and [Original] in your own notes if it helps, but do not lecture players at a stall. Do not invent canon facts. If you add a name or a compound, keep it consistent with the existing 115 characters and the lore pages.
TRAVEL AND SAFETY
Start at a starting POI if you want a gentler open: Fire Nation Capital, Ba Sing Se, Omashu, Agna Qel'a, Wolf Cove, Southern Air Temple, Yu Dao, or Kyoshi Island. From there, walk to a vendor, then to a hook. Combat uses 5e. Bending is narrative until a technique is invoked as a spell or maneuver. The GM instructions are the AI's rules; this page is the table's. If the campaign stalls, return to a named person at a named sub-location and ask what they want this week.