The Demon Clan is known to be the most dangerous one. There are many types of demon (including red, grey and blue Demons), but the Demon king has an elite group that are known as The Ten Commandments. Each one of them has a specific curse tp which they are named after, making them more dangerous (breaking one of the rules in their presence will curse said person; lying in the presence of the Truth Commandment will turn the liar to stone for instance).
The Demon King is unbelievably powerful to the point where Meliodas is overpowered. His innate power “The Ruler” allows him to absorb all magic thrown at him. It is unknown if you need to be as strong as him to actually hurt him. He can also use elemental attacks and bestow curses and blessings on others, even transferring abilities between people. One such curse is the immortality he gave Meliodas, allowing him to live forever in exchange of losing his emotions. He has full power over the commandments, taking and giving them on his order.
As a Demon, you are able to control the purgatory flames which can burn and rot away anything, you also can create a black substance which allows you to fly, to heal wounds those and protect yourself from devastating attacks. The last thing is the Indura form; This can only be done by Demons with a power level of 50000 or more (only 7 Demon characters have such a power), this power allows you to gain an immense amount of strength, speed and endurance at the cost of six of the seven hearts you may have and your ability to reason. There is a form that may be more useful called “Assault Mode”, though this is used by Meliodas, though it is debatable how the power and form relate to one another. Demons can also convert others into demons through having them ingest demon blood, though this can cause explosive death. Demons live for a maximum of 1000 years, though Meliodas was made immortal by his father, the Demon King, which is how he survived for over 3* that long.
Demons are not all evil. Meliodas and a demon called Gowther both showed traits that defied the clan, despite both being Commandments.
The Goddess Clan is known as the most powerful Clan next to the Demons. The strongest of them are known as the archangels, who are a match and the Goddess equivalent to the Demon Clan’s The Ten Commandments. They serve a being called “The Supreme Deity”. The archangels have an ability called a “Grace”, which is the Goddess version of a commandment. The other difference, sans being only 4, is that the user a special ability that augments their magical power and raw power. Ocean and Tornado allow godlike control over water/wind while Flash gives speed and Sunshine gives strength.
Like The Demon King, The Supreme Deity is unbelievably powerful to the point where Meliodas is overpowered. While we don’t see an innate power, she has power over the graces, can manipulate nature and can bestow Curses and Blessings, whether it be immunity to curses or making some reincarnate over and over; such as her own daughter
A Goddess has many abilities, the only well known ability is Ark; they generate light that counteracts Demons. Just as Fairies, Goddesses are able to fly thanks for the huge wings on their back. The wings are symbolizing their rank, the bigger the wings or the more you have, the stronger you are. Goddesses are also able to heal others or themselves, can resurrect the dead (yet to be proven) can erase "abominable" souls with Purge, can possess others and some can even reverse time. One last ability is “Breath of Bless”; a highly powerful Goddess can empower others. Though those affected become fanatical zealots loyal to the Goddesses with no regard of their injuries, this is why the Demons call this ability “Cheat Hope”. It is unknown how long Goddesses live for.
Do not think that they oppose the Demons that the Goddesses are all good. Ban was told by a Goddess that she’d resurrect his dead lover… in exchange of killing his best friend and captain, and they destroyed an entire village as they were “harboring” a wounded benevolent demon. A further misconception is that the Goddess Clan could be that they are all female, there are male members.
The Fairies are a well known Clan which is connected to nature. The Fairies are lead by the Fairy King, who is chosen by the Sacred Tree.
A Fairy is able to change his or her form into anything (mostly human). Just like the Goddess clan, the Fairies are able to fly thanks to their butterfly-like wings/telekinesis. The Fairy King himself is able to control the nature through the power Disaster, and unlike other Fairies their wings are larger.
The Fairy King is given a special weapon by the Sacred Tree known as a Spirit Spear. The Fairy King himself gets feared and respected by any other Clan due to his immense power.
The Giant Clan is well known for being extremely strong, to the point their leaders are picked through physical combat. Unlike the Fairy Clan, the Giants are in scarce numbers these days, due to being hired as mercenaries to fight in various wars.
Just as the Fairy clan have a connection to nature, the Giants has a deep connection with the Earth. They are able to turn stone into sand or are able to bend earth like how they want. A Giant has the highest endurance and are able to survive the worst attacks, but they are not invincible. There is a technique they can learn called the “Drole Dance”, named after the founder of the Giant clan and one of the most powerful Giants, Drole. Those that perform this correctly gain a better connection to the earth and grow stronger as a result.