Alioth is named after one of the seven stars in the constellation of the Big Dipper. It has a huge outer shell that resembles a ship of some sort. It attacks by dropping neurotoxins formed within itself which are potent enough to kill humans in a very short time.
Before battling Alioth, it is speculated that Alioth's core will also use its neurotoxin as a means to protect itself. Makoto will then hand over a canister filled with a neutralizing agent that will temporarily negate all of Alioth's toxins when placed in one of three specific positions on the battlefield. If the neutralizer is not used or expires, any attacking team will take damage from the poison. Any leftover toxin shots on the battlefield, exploded or not, will also be removed once the neutralizer is activated.
During the battle, Alioth will also, from time to time, fire toxin shots around the battlefield. These must also be eliminated before their turn arrives, otherwise they will explode and spread toxins around their location. If a toxin shot happens to land directly on a team, it explodes immediately, damaging the team and spreading on the ground around the point of impact.
Demons with racial skills that allow high movement, such as Devil Speed and Winged Flight are recommended in this fight to set the neutralizer as soon as possible, as well as teams with high HP, due to Alioth's unique skill "Marked Wing" which will deliver high damage to any teams battling in a non-neutralized toxin area, and its Beast Eye ability that allows it to attack twice per turn. Once the neutralizer is activated, "Marked Wing" will become less effective. Otome Yanagiya is a good party member to bring to the fight with Alioth, since her Fate grants her resistance to Electricity (protecting against Ziodyne) and Curse (protecting against Marked Wing).