Megrez is named after one of the seven stars in the constellation of the Big Dipper. It arrives on Wednesday and is the fourth Septentrione to appear, first appearing in the Pacific Ocean and spreading the prismatic human-sized buds that its body hosts and produces over Japan. If the buds don't explode on impact upon reaching their destination, they can land wholly intact and act autonomously to deal damage and cause tremors, though they are not capable of moving on their own without being launched from Megrez's body beforehand.
Megrez's buds take on a multi-colored cone shape, similar to Dubhe's lower half. Its true body is orange and spherical, with multiple spikes (its buds) protruding from it.
Megrez specializes in regeneration. Whenever you attack, it will move to another location and regenerate, recovering a certain amount of health. Each turn, it will make a minor regeneration and, after being attacked, will release buds to deal damage to all teams.
Begin the battle by clearing the Miasma. Megrez will not move until you attack it. After dealing with the other demons and clearing the miasma, begin attacking Megrez. Its movement patterns are north to north-east, north-east to north-west, and north-west to north. You may want to set up a team at each point to prepare for Megrez's movement. You may choose whether you want to defeat the buds, or set up a healer for the teams fighting Megrez.
Megrez is weak against Ice so leaders such as Fumi, Otome, or Io will be helpful when combined with Ice Dance. Equipping Anti-Force will also help in battles, as well as having demons who are strong against Force-type attacks, use strong Ice-spells, or allow quick movement. Having Avians that have earned the Winged Flight racial skill helps greatly in this battle as it allows leaders to travel to and disable isolated miasmas, while also being able to stay outside of Megrez's attack range of 6 until they are ready to attack.
- In the anime, JP's names two discrete Megrez bodies "Megrez N" and "Megrez O", most likely stemming from their surfacing areas, those being Nagoya and Osaka. Although it is not mentioned in the anime itself, it can be surmised that the third body was named Megrez T, standing for Tokyo.