The Fallen race are from the Aerials species and are for the most part related to Darkness, most of them have the trend of resisting Darkness or ailment attack. The Fallen demons are usually Neutral-Chaos except in Shin Megami Tensei and Majin Tensei II where they are Dark-Chaos, in Giten Megami Tensei: Tokyo Mokushiroku there are two races: the Datenshi are Dark-Chaos and the Futenshi are Neutral-Chaos. They can be thought of as a Neutral version of the Tyrant. In religion, they are fallen angels that sided with Lucifer in his rebellion, whose bodies were twisted and made ugly upon their defeat.
In Giten Megami Tensei, the Fallen race was divided between two alternate races. The first is named Futenshi (不天使*)?, being Neutral-Chaos aligned, and the other is traditional Fallen being Dark-Chaos aligned. The difference between the two lies in how they fell from the heavens:
"Angels who descended to Earth of their own volition, unlike the Fallen. They observe human essences and distinguish them as knowing pain and sadness or joy and passion. They are guardians of beauty and decadence, nurturing pleasures of the flesh and rejoicing in passion and enthusiasm. They have strong senses of rhythm, making them proficient at dancing and fighting."
"Angels who were banished to the Expanse after rebelling against the Creator God. Once noble, their existences have now become soiled in grudge and sorrow. Their behavior is rife with falsehood, and they actively interfere in human affairs as they seek revenge on Heaven."
The Fallen race has the Sacrifice Racial Skill. If the Fallen defeats an enemy, some HP and MP is restored to the entire team, based on the level of the defeated enemy.
The Fallen race has the Sacrifice Racial Skill. If the Fallen defeats an enemy, the entire team regains HP equal to the defeated enemy's level and MP equal to half that amount. Stronger members of the Fallen race have this skill changed to Fallen's Mark, which, in addition to the above, also grants the Fallen an option to steal MP from an enemy team up to 3 squares away, at the cost of the Fallen's own HP.
Prior to a patch in August 2014, the Fallen Angel race in Shin Megami Tensei IMAGINE was the only race that had no assigned genders for any demons.
Becoming a Fallen does not mean becoming loyal to Lucifer or even renouncing Law, as shown by Abdiel in Shin Megami Tensei V; rather, a Fallen gains the ability to act outside the letter of the orders given to them by YHVH, including in ways that uphold the spirit.
* Asterisk denotes race that has been put under different species throughout the series. Italic font denotes the race/species name (not in katakana for Western loanword) has not yet received any official English localization.