Sidhe Traits
Ability Score Increase. Your Charisma increases by 2, and your Dexterity increases by 1.
Age. Sidhe have no concept of age as they are an immortal race, reincarnating back in their native land after death. The average sidhe appears fully grown after 20 years.
Alignment. Most sidhe are chaotic by nature, though some of their rulers are lawful.
Size. Sidhe average 5’6 to over 6′ tall and have a lithe build. You are a medium creature.
Speed. Your base speed is 30 feet.
Languages. You can speak, read, and write Common, Elven, and Fey.
Eternal Creatures. Your creature type is fey. You are not a creature of this world; your magic is your own; you have no use for the magic of Immortals. You cannot gain or take classes, archetypes, or feats that grant divine magic such as cleric, druid, ranger, or paladin. You generate your magic from your ties to the Good Kingdom, offers of power from outside influences are meaningless to you, so you cannot take levels in the warlock class.
Fey Magic. At 2nd level, you learn a cantrip from the Illusion and Enchantment schools from the wizard’s spell list. At 4th level, you learn a 1st level spell from one of those schools. Every other level after, you learn one spell of the next level until level 20 when you learn a 9th level spell. You can cast each of these spells once per long rest (use Charisma as your spellcasting ability). You lose this ability while wearing or carrying iron.
Water Breathing. You can breathe water as well as you can breathe the air.
Iron Allergy. You cannot stand the touch of iron. You cannot cast spells while wearing or touching iron weapons or armor. Items with a +2 enchantment or better are not considered to be made of iron. You have damage vulnerability against iron weapons.
True Fey. You are immune to nonmagical diseases and can see other fey that are invisible. As you reincarnate quickly into a new form in the Good Kingdom, spells that raise you from the dead only work if cast within 10 minutes of your death. You can never become free-willed undead.

Ability Score Modifiers/ Requirements

Disease, Death, and Aging: Death is seen in a special light by all fairies. It merely marks a change in the cycle of their existence, when their spirit abandons one body, and is reborn as another fairy (after 0-999 years of mortal time). Age has no meaning for the Good People, and they do not suffer natural diseases. (Magical diseases, such as mummy rot, may affect them.) Death comes either through violence, accident, or magic; or, more typically, a fairy tires of its form, and chooses to give it up and be reborn.
The absence of a fear of death or aging is a notable aspect of fairy character, even more extreme than that of elves. It gives them a truly experimental, adventurous outlook on existence. And, like elves, fairies are immune to the paralysis of ghouls, since this preys on a victim’s fear of death.
In spite of this, few fairies willingly jump into violent deaths; they still feel pain and prefer to avoid it. Besides, adventures are more fun if you can see them through to the finish. (Also, a reincarnated fairy loses the powers and experience, and usually the memories of its previous existence.)

Fairies and Undead: Undead are the great enemies of fairies, as they are of druids. Both the Fair Folk and undead are ageless, and apart from normal, living beings; but while the fairies seek to promote life, the undead wish to destroy it.
Very powerful fairies may learn the secrets of animating dead, but this art has been forever and absolutely forbidden by the Fairy Court. Proof of participation in such heinous evil is sufficient ground for exile from fairy society. Fairies who become involved in necromancy, it is believed, are reincarnated not as fairies, but as incorporeal undead spirits (especially banshees).

Invisibility: All of the fey races have the innate ability of invisibility to mortals. Creatures with second sight (see below), which includes Other fairies, are also able to perceive persons and objects that are invisible to mortals; hence, this is different from normal magical invisibility, which makes its subject disappear to everyone.
Sometimes it is possible to perceive the faintest glimmer in the air, like the shimmering of air over pavement on a hot day, when a fairy is present. This especially occurs in the evening after sunset, when much of the light is near the violet end of the visible spectrum.
The spell detect invisible will reveal creatures and objects invisible to mortals; dispel magic will cause a fairy to become visible, but after a round the fairy can will itself back to invisibility to mortals.

Second Sight: Second sight is a peculiar ability, common to all fairies, that sometimes occurs among mortals. It enables one to recognize a fairy’s true form, even if the fairy is invisible to mortals, polymorphed, or shapechanged.
This ability (has been theorized to be) is an extra-sensory perception or intuition involving time. Basically, from perceiving the fairy’s visible, normal shape at another point in time, the seer recognizes the magical being for what it is.
Second sight is often associated with prophetic visions; a funeral, for example, might be seen weeks, even years, before it actually occurs. The prophetic workings of second sight seem sporadic and are not well understood; and, further, a seer is often unable to tell when he is seeing normally or with second sight. Hence a gifted seer may greet a sidhe, thinking him a normal person, though the fairy is invisible to everyone around him; or a prophetic vision may be thought an occurrence in the present. In game terms,
the DM may use second sight to pass on cryptic information to players, but be careful not to abuse or overuse the power.
Some exceptional mortals may have this ability from birth (perhaps on account of a fairy ancestor); or it may be bestowed magically. The Good People jealously guard its bestowal. Human folklore describes a woman who accidentally smeared ointment of second sight on one of her eyes. When she later greeted a fairy in a marketplace, not even realizing he was invisible to the other people, he asked with which eye she could see him. After she told him, he removed it, and she of course never again perceived the Fair Folk (or anything else, for that matter) with it.

Spellcasting: All Sidhe are natural Fairy Spellcaster and can cast Fairy Charms after the Normal Monster Level. Fairy Charms are a special type of spell that only members of the Fairy Folk races can cast.

Warrior or Rogue? All sidhe beyond normal monster level combine their fairy spellcasting ability, with either fighting or thieving skills; they may therefore be warrior sidhe or rogue sidhe. Most are the former; to be a rogue sidhe, a minimum Dexterity of 8 is required.
Both class combinations progress on the same level advancement table; but while warrior sidhe have
eight-sided Hit Dice, those of the rogue sidhe are four-sided.
Warrior sidhe can make multiple attacks at higher levels, like fighters. Rogue sidhe have the special skills of thieves of equal level (lockpicking, backstabbing, etc.).

Weapons / Armor Restrictions: No sidhe may use weapons or armor fashioned of iron. Otherwise, warrior sidhe can use any weapons or armor open to fighters, and rogue sidhe may use any open to thieves. Sidhe may use any magic item permitted to magic-users and either fighters or thieves, according to class combination.

Saving Throws: Warrior sidhe make Saving Throws as fighters, and rogue sidhe as thieves, of the same level.

Breathing: All sidhe, since they often have underwater homes, may breathe water and air with equal facility.