In October 2018, Niantic added the first third generation to Pokemon GO as part of the game's Halloween event. Speculation has pointed to the first fourth generation Pokemon coming to the game during this year's Halloween event, and while we still don't have a concrete release date, a new trailer does seem to indicate that estimation is not far off.

In a new trailer, Niantic has teased that the first fourth generation Pokemon are coming to Pokemon GO soon. The trailer shows a variety of different locations, and features brief glimpses at the fourth generation starter Pokemon, the grass-type Turtwig, the fire-type Chimchar, and the water-type Piplup. It then ends with a tease of one of the legendary Pokemon that will be added to the game as part of Gen 4 with what appears to be Giratina.

Check out the first Pokemon GO Gen 4 trailer right here:

If Niantic adds the first Gen 4 Pokemon to the game as part of the Halloween event as anticipated, then it would make sense for Giratina to replace Mewtwo in legendary raids. Giratina is a ghost-type Pokemon, after all.

Of course, it's also possible that the first Gen 4 legendary added to Pokemon GO will be something completely different than Giratina. There are a number of Gen 4 legendary Pokemon to choose from, and it could very well be Dialga, Giratina, or Palkia instead. Ultimately, fans will just have to wait for Niantic to be ready to share more information on that front to be sure.

In the meantime, it will be interesting to see exactly when Gen 4 Pokemon will be added to Pokemon GO. Usually new Pokemon are added to the game not long after they're teased, so fans should be able to expect the first fourth generation Pokemon in Pokemon GO by the end of the month. And with Pokemon Let's Go Pikachu and Let's Go Eevee right around the corner, the game's proper PvP mode could very well come packaged with the Gen 4 update, but we'll just have to wait and see.

Pokemon GO is out now for iOS and Android mobile devices.