The Canim are a large wolf-like race. They stand upright to a height of at least 7 feet. Their armies are divided into at least two castes: warrior and ritualist. The social customs of the Canim are consistent with a race of predators: Any signs of weakness will lead them to attack. If a leader appears weak, he is replaced. They have excellent night vision. Not much is known about them to the Alerans. Most of their knowledge is learned during the Canim's raids on the western coast of Alera.
The Warrior caste is the elite of the fighters for the Canim army. They carry traditional weapons and armor, though the armor is black which is consistent with a predatory race that hunts at night. Nasaug is a leader of this caste. In addition, some warriors wear the scarlet steel that is seen in Canim weapons.
Those of the Ritualist caste are the spellcasters of the Canim. The Canim do not wield furies, but are still capable of using magic. The ritualists have been known to do many large-scale sorceries. They have sent large storms, turned the sky red, and can call forth lightning to attack an area or single target. Sarl is a leader of this caste.
The Raider caste forms the bulk of the Canim army, and is made up of farmers and lower-class folk who are conscripted. In battle, they wear lighter armor, and use rusty farm tools as weapons. Throughout most of history, the Raiders are the Canim that the rest of Alera has fought. However, despite being "light" infantry, they are still formidable in combat.
In Academ's Fury
The Canim are first presented in Academ's Fury. Tavi meets Ambassador Varg in Varg's attempt to warn the First Lord about the guards he's had go missing. He later discovers and warns Tavi about the Vord nest in The Deeps.
In Cursor's Fury
A large fleet of Canim ships is seen approaching the western coast at the beginning of the book. A Cursor notes it and attempts to report it. Along his way to Aleria Imperia, he finds the First Aleran, a group of legionnaires made up of soldiers from every realm in Alera, which Tavi has been put in charge of. The First Aleran is moved to Elinarch and, in the process, run across several small groups of Canim attacking the local steadholts.
Tavi discovers that the raiding parties are the Canim equivalent to farmers and that they have yet to encounter the main Canim force. He also discovers that the Canim have completely destroyed the fleet they sailed in on. The Canim attack isn't just a raid, it's an invasion.The Canim are eventually routed at Elinarch. As they're retreating, Tavi finds a female Canim that has recently given birth. The Canim haven't just invaded, they're fleeing their homeland and are trying to re-establish a home.