Complete fairy guide

Fairy is a wonderful companion in your character’s life.
It gives additional attributes and can be taught some skills that are very useful in a battle!
There are two types of fairies: first generation and second generation.

First generation:
These are normal fairies that drop from boss mobs and from Flowery chest (on receiving 1st class promotion and level 10).

 A Fairy Box is necessary to receive to get one of the beautiful companions:
 Fairy of Life
 Fairy of Darkness
 Fairy of Virtue
 Fairy of Kudos
 Fairy of Faith
 Fairy of Valor
 Fairy of Hope
 Fairy of Woe
 Fairy of Love
 Fairy of Heart

Each fairy can grow any attribute (up to level 41): spirit, strength, constitution, accuracy, agility.
Fruits are sold in the Item Mall, and are obtained in the game also (you can buy it from players or exchange for reputation from NPC - Baby near Argent Teleporter):

Great fruits (+2 stats):
 Great Shaitan Biscuit - Can increase Spirit of the fairy by 2 points.
 Great Argent Mango - Can increase Constitution of the fairy by 2 points.
 Great Zephyr Fish Floss - Can increase Accuracy of the fairy by 2 points.
 Great Icespire Plum - Can increase Agility of the fairy by 2 points.
 Great Snow Dragon Fruit - Can increase Strength of the fairy by 2 points.

Normal fruits (+1 stat):
 Shaitan Biscuit - Can increase Spirit of the fairy by 1 points.
 Argent Mango - Can increase Constitution of the fairy by 1 points.
 Zephyr Fish Floss - Can increase Accuracy of the fairy by 1 points.
 Icespire Plum - Can increase Agility of the fairy by 1 points.
 Snow Dragon Fruit - Can increase Strength of the fairy by 1 points.

Fairy can be taught skills:
Protection, Berserk, Magic, Recover, Meditation, Cooking, Crafting, Manufacturing.

You can learn 3 skills in total for one fairy and it’s better to learn standard skills.

Important! Once learned the first skill, there is a chance that when learning the second, the first will disappear. Similarly, if you have learned two skills when learning the third, one of them may change.

For example:
For magical classes, the following skills are more suitable: Meditation, Magic, and Recover.
For physical classes: Meditation and Berserk.
And skills of Cooking, Crafting and Manufacturing are studied for life skills. (we suggest to use another pet for life skilling)
The fairy has stamina that ends with time. The fairy starves and dies.
To prevent this, it needs to be fed:
 Fairy Ration
 Auto Ration
 Pet Food

To feed a fairy, you need to double click on the ration you want to feed it with ("chicken leg" will appear instead of the cursor), put on the fairy in your inventory and left-click. 
There are levels where your fairy may not level up!
12 lvl - 80% success
35 - 80% success

Second generation:
These are fairies which are obtainable via the marriage of two first generation fairies.
2nd generation pet is often used for the one and only purpose: fairy possession.
It doubles the stats of the fairy for 3 minutes.
Example: Fairy of Constitution on possession will give (Fairy level * 1) additional constitution stats.

Wedding conditions of the first generation fairies:
To receive 2nd generation pet you will need:
20+ level of the both fairies;
Full stamina on both of them;
Necessary pet marriage loots (the exact loot will be listed below with the fairies names);
Full stamina on both of them.
IMPORTANT! Preferably use a pair of fairies with the same attributes to get the preferable result.
Each fairy will give you the stat of it's name when possession is used except Fairy of Evil and Fairy of Luck. They will give experience and drop rate.

 Fairy of Constitution (Gives constitution on possession)
 Demonic Fruit of Courage — x1
 Cracked Arabic Pearl — x10
 Sorrow Archer Carcass — x10

 Fairy of Agility (Gives agility on possession)
 Demonic Fruit of Aberrant — x1
 Shark Fin — x10
 Swamp Wood — x10

 Fairy of Strength (Gives strength on possession)
 Demonic Fruit of Strength — x1
 Arabic Pearl Fragment — x10
 Wailing Warrior Carcass — x10

 Fairy of Spirit (Gives spirit on possession)
 Demonic Fruit of Intellect — x1
 Polliwog Tail — x10
 Wailing Archer Carcass — x10

 Fairy of Evil (Increased EXP on poss. Fairy level x 1.5% = EXP bonus)
 Demonic Fruit of Mystery — x1
 Sparkling Arabic Pearl Fragment — x10
 Mud Slice — x10

 Fairy of Accuracy (Gives accuracy on possession)
 Demonic Fruit of Energy — x1
 Fish Spike — x10
 Mud Chunk — x10

 Fairy of Luck (Increased drop rate on poss. Fairy level x 2.5% = Drop bonus)
 Demonic Fruit of Acidity — x1
 Tasty Squid Meat — x10
 Skeleton of Sorrow Warrior — x10

NPC Pet Assistant - Langa will help you to marry your fairies:

Also you can find conditions to conceive fairies from him.
Choosing “Fairies marriage” first of all you need to insert the fruit, and only then fairies:

After the first generation fairies wedding we will get:

 Second generation fairy
 Fairy Possession

There are 3 types of possessions: Novice Fairy Possession (after marriage 20+ level fairies), Standard Fairy Possession (after marriage 25+ level fairies), Expert Fairy Possession (after marriage 35+ level fairies).

Most often Expert Fairy Possession is chosen.
So as when you're using the skill, the fairy will consume less stamina.
After the wedding, the first generation fairies do not disappear, but their level is reduced by 4.
Attributes of the received second generation fairy will have 1/8 of "parents" attributes.
If parent pets have lv20, then the second generation fairy will be (20+20)/8 = 5 levels.
If one parent has lv20, and the other has lv40, the offspring will be (20+40)/8 = 7 levels.