The Septentriones in Shin Megami Tensei: Devil Survivor 2 are mysterious invaders that arrive in Japan and begin attacking the country on a Sunday.
The Septentriones show up at least once a day and there is a time limit of seven days to defeat them. They have been employed by Polaris to aid in its destruction and recreation of the world. The main targets of their attacks are the radio towers in Tokyo, Nagoya, and Osaka, as these towers are actually projecting a barrier that has been preventing their respective regions from disintegrating into the Void. Once all Septentriones have been defeated, the path to Polaris will open, allowing humanity to seek an audience with it.
- Dubhe: The pink mass on its top can expand and explode.
- Merak: It is capable of creating small, red sub-units that explode upon reaching their destination.
- Phecda: While immune to almost everything while whole, it is also capable of splitting itself into two, while sacrificing its nigh-invulnerability.
- Megrez: It appears from the Pacific Ocean and launches the needles that are on its body at the various areas of Japan. Those needles are capable of moving on their own and can cause earthquakes.
- Alioth: It flies far above the attack range of the party's demons while dropping neurotoxins at its targets below.
- Mizar: It is made up of smaller versions of itself that grow rapidly. If any grown clones are attacked, they too can split into smaller Mizar clones.
- Benetnasch: It can split itself into four pieces, control the minds of team leaders so they cannot injure it, and disable any attempt to summon demons. It can also replicate the abilities of the other Septentriones to a limited degree.
- Alcor: Appears on the last day in order to open the path to Polaris.
- Polaris: A god-like entity and mastermind of the Septentrione invasion. It rules multiple universes from the Heavenly Throne, and thus is able to control their fates.
- The eight stars in the Devil Survivor 2 title logo points to the Septentriones needed to beat in order to reach Polaris. Seven stars under the logo points to Dubhe to Benetnasch, while the last one above the 'D' in Devil title is Polaris due to its positioning relative to the Big Dipper constellation.
- The Septentriones are written as "Septentrions" in the original Japanese.
- In the game the larger Septentriones like Merak and Megrez were scaled down to have them fit, with the anime showing how big they truly are.