Evidence is mounting that Legendary Pokémon are coming to 'Pokémon Go' very soon

Mewtwo Pokemon GO concept

After more than a year of speculation, evidence is mounting that ultra-powerful Legendary Pokémon are coming to Pokémon Go very soon.

Pokémon Go creator Niantic Labs has never publicly acknowledged that Legendaries are coming or given an expected release date, but there are several reasons to believe we'll see creatures like Mewtwo and Lugia in a matter of days.

If don't know, Legendaries are extremely rare and powerful Pokémon from the original game series. And until now, they've been completely absent from Pokémon Go, even as the game has added more creatures from the second generation of Pokémon.

All signs point towards Niantic finally unleashing Legendaries at the first-ever Pokémon Go Fest event in Chicago's Grant Park on July 22. The ticketed event is expected to draw 20,000 players, hearkening to the game's original video trailer that showed thousands of players fighting Mewtwo together in Times Square.

Here's all of the evidence that points to the imminent release of Legendaries in Pokémon Go:

An analysis of the app's code in late June by The Silph Road found new references to Legendaries, including the fact that they'll be encountered through the game's recently released Raid Battle feature.
The Silph Road believes that Legendaries won't be able to defend gyms (likely because of how powerful they will be in relation to normal Pokémon), but the site says that Legendaries should be able to attack gyms alongside normal Pokémon.
Graphics have also been uncovered in the game's code for dark Legendary eggs, badges, and a Legendary raid pass.

New Legendary Badge features Lugia! http://pic.twitter.com/LGRDwjMpY3
— Pokémon GO Hub (@PokemonGOHubNet) June 20, 2017

A recent promotional banner for Pokémon Go in the Indian App Store mentioned "the first legendary Pokémon."
Niantic has been covertly testing tier 5 Raid Battles in the game. Players have spotted the tests in the nearby tab, but haven't been able to find the raids on the map. The highest Raid Battle tier currently available is tier 4.
Niantic announced earlier this week that players at July 22's Chicago event will have to participate in special challenges alongside players around the world to unlock a worldwide "Mystery Challenge." Based on the game's first trailer, lots of players will have to participate in a Raid Battle together to take down Legendaries.
The Pokémon Go Fest event in Chicago will feature an "Ultimate Gym," which suggests that Legendaries will first be unveiled there.