Downfall Timeline
The Hero of Time falls. Ganondorf claims the complete Triforce, and Hyrule endures its darkest, longest history.
Fork point: Ocarina of Time
Diverges from Shared Trunk (Before the Split)
The Story Arc
The branch nobody talks about in-fiction: the Hero of Time loses. Ganondorf seizes the full Triforce, and Hyrule's history becomes a long war of seals, declines, and stubborn survival. A Link to the Past opens this era with the Imprisoning War's aftermath and the corrupted Dark World.
Its hero then drifts through Link's Awakening's island dream and the linked Oracle adventures. Generations later, A Link Between Worlds replays the ancient conflict through the mirror kingdom of Lorule, and Tri Force Heroes follows a few years after. At this timeline's far end sit the two games that started everything in release order — the original Legend of Zelda and The Adventure of Link — recast as the era of Hyrule's greatest decline.
A correction worth knowing: A Link to the Past is commonly misremembered as a pre-split 'era of creation' game. Both official charts place it here, opening the Downfall branch.
Games, in chronological order

A Link to the Past
Set on the timeline where Link was defeated by Ganondorf in Ocarina of Time and the villain claimed the full Triforce, this SNES classic sends a new Link into the corrupted Dark World to rescue Princess Zelda and six maidens.

Link's Awakening
Shipwrecked on the dreamlike Koholint Island, Link must wake the Wind Fish by gathering eight musical instruments — only to discover the entire island may be nothing more than the Wind Fish's dream.

Oracle of Seasons
Link travels to Holodrum to stop General Onox from imprisoning the Oracle of Seasons, Din, using the Rod of Seasons to manipulate the land itself — one half of a pair of linked adventures developed alongside Oracle of Ages.

Oracle of Ages
Link's companion adventure to Oracle of Seasons sends him to Labrynna to rescue the Oracle of Ages, Nayru, from the sorceress Veran, using time-travel puzzles built around an ancient Harp.

A Link Between Worlds
A spiritual sequel set generations after A Link to the Past in the same Hyrule, where Link gains the ability to merge into walls as a living painting to stop the sorcerer Yuga from reviving Ganon.

Tri Force Heroes
A three-player cooperative spin-off in which three Links, cursed alongside their kingdom's fashion-obsessed princess, must stack atop one another as a 'Totem' to solve puzzles and defeat the Drablands' witch sisters.

The Legend of Zelda
The original: Link explores an unmarked overworld and eight dungeons to reassemble the shattered Triforce of Wisdom and rescue Princess Zelda from Ganon. Chronologically, its unnamed hero is a distant, unrelated descendant of the earlier Downfall-branch heroes.

Zelda II: The Adventure of Link
A direct sequel to the original, blending side-scrolling action with overworld exploration as Link seeks to wake the sleeping Princess Zelda and prevent Ganon's followers from resurrecting him — the final chapter of the Downfall Timeline.