The Two Armies
The army sent by the Empire to deal with the Japanese forces stationed at Alnus Hill where the Gate is located is obliterated. Emperor Molt calls for the vassal states to attack them, just to be defeated with huge casualties as well, a move planned in advance by the emperor to avoid the vassal states taking advantage of the Empire's weakened state. As Emperor Molt decides to delay a possible advance from the JSDF with a scorched earth maneuver, the President of the United States decides to leave the investigation of the Special Region to the JSDF for a while, and Itami is assigned to lead the 3rd Recon Unit, created to survey the nearby cities and points of interest. After passing by the village of Coda, the 3rd Unit finds a massive Fire Dragon burning the nearby forest and then attacking and destroying a nearby settlement.
Aired 11/07/2015EP 2 - The Two Armies

Gate
The military fantasy series begins when a gate appears in Tokyo's Ginza district sometime in the 21st century. From the gate pours out monsters, knights from middle-age Europe, and other fantasy-like beings, and they kill many of the citizens of Tokyo. This event is known as the Ginza Incident.
The government sends a small group of soldiers from the Japanese Self-Defense Forces (a replacement for Japan's military) to the alternate world beyond the gate. Led by otaku soldier Youji, they find that the villages in the world are being attacked by a dragon. An elf girl who is a survivor from the dragon's rampage joins the group in their travels across the dangerous new world.
(Source: Anime News Network)