Metis
Metis is a term used to describe a rare breed of Garou: the offspring of two Garou who broke the Litany for love or lust. Metis are born in the Crinos form and that is their natural form - however, they are deformed and sterile. This result also comes from inbreeding in some other Changing Breeds, although some of the Fera have their own terminology to describe such creatures.

Garou glyph for Metis.
Except for the legendary Perfect Metis, all other metis are born with an innate flaw. This disability may be a physical deformity (such as a withered limb), a mental disability (such as severe mental illness), an intellectual impairment, or even a spiritual disability (such as always reflecting their Crinos form in mirrors).
Despite their deformities, metis do enjoy some advantages. Their natural form is Crinos, so they are naturally better at combat than their brethren. They also have more Gnosis than Homid cubs, giving them a spiritual advantage. Lupus have more Gnosis, but are often baffled by the human world. The idea of walking upright and having use of hands can confuse and frighten Lupus cubs. Metis cubs can walk on two feet or four feet (unless prevented by a limb deformity), and so are used to perceiving the world from multiple perspectives. Metis are also raised in Garou society, so they usually have a far better grasp of rituals, the spirit world, social customs, and other aspect of Garou society that homid and lupus cubs don't learn about until after First Change.
But because metis are born in the huge Crinos form, they live the first six to eight years of their life with their Rage close to the surface, giving them terrible tempers even compared to human babies. They can cause grave harm with their claws and teeth even by accident, starting with their mother's body. Metis also return to Crinos form when they die, creating a significant problem for the Garou Nation to maintain the Veil - as a deceased Homid and Lupus Garou would leave behind only human or wolf corpses, respectively, regardless of what form the Garou was in at the time of death. Metis corpses must be disposed of in some way that makes them completely unrecognizeable.
Not all metis are raised in Garou society, however. Because they are trapped in Crinos until First Change, they must be kept out of sight of humans. In an urban or suburban sept, this means they spend the majority of their childhood locked away from people and not even allowed outside. At small septs, they may well be the only metis, so will have no one to interact or play with, stunting their emotional growth. They may have extreme difficulty coping with groups of people once they undergo first change, and lack basic social skills for dealing with both humans and wolves.
Metis are generally looked down upon by most Garou as they are a result of two Garou breaking one of the tenets of the Litany: "Garou Shall Not Mate With Garou". Some tribes kill their metis outright or treat them so cruelly they might wish for death or even defect to the Black Spiral Dancers. Sometimes, the mother is punished by forcing hr to kill her cub, although the fathers of metis rarely receive as much punishment. Other tribes require the parents to raise the cub as punishment for their sins, but do not officially punish the child itself. Unofficially, metis still have to work much harder than homids or lupus to gain respect.
Metis at larger septs are generally a bit 'luckier' since there may well be other metis cubs of similar age in residence that they can interact with. Larger septs are also more likely to have someone experienced with raising metis cubs, who may arrange for a visit to another sept with a metis pup to get a lone metis some much needed social interaction.
Garou views on Metis
The Fianna are known to be particularly abusive of metis, considering any physical deformity a sign of spiritual inferiority and inherent corruption. They treat even homids and lupus with minor physical flaws as lesser creatures. The Red Talons frequently kill metis because they are unable to keep up with the pack, but bear them little personal malice if they are strong enough to survive. The Get of Fenris and Shadow Lords often tolerate metis only so far as they prove useful in battle or politics, but also tend not to heap as much abuse on them as some tribes. Black Furies, who normally give away or even kill their male cubs, often keep male metis and accept them into the tribe. Treatment of the metis varies between septs, but none of any gender has ever been elevated to tribal leadership.