The Wishing Potion
1) This quest starts with Alchemist Matild who is standing in front of her cottage due west of the Ivory Tower. In theory it can be picked up at level 30, but since the very first quest monster is lvl 47, solo players should not start this quest before they are level 46.
2) When you talk to Matild she tells you about a secret book the location of which she has discovered in an alchemy text. Matild gives you said text which goes in your quest inventory. Click on it and you will see that the secret book is kept by the Secret Keeper Tree in the Cruma Marshlands, north of Dion.
3) The Keeper Tree's precise location, near the western exit of the Cruma Marshlands, is marked on your map. It is lvl 47 and not easy to kill, so either don't go there until you are level 46 or do this in a group.
4) Return to Matild. If you procure some ingredients for her, she will make you a Wishing Potion that will, in a random way, fulfill many of your wishes. The Wishing Potion is a mixture of two fluids, therefore Matild gives you two recipes. Together they make quite a long list.
5) The monsters furthest away are the Whispering Winds (lvl 30, passive), directly on the coast opposite the Kamael island and quite some distance north of Gludin Village. You need only one Wind Soulstone and on average you have to kill about 15 of those spirits for it. The same goes for all the following monsters. But this is really an average value - sometimes you are lucky on the first try, but once it took me almost an hour until I had my quest item.
In the Ant Nest, on the northern edge of the Wasteland, you need to kill Ant Soldiers (lvl 35, poisonous) and Ant Warrior Captains (lvl 36) until you get an Ant Soldier Aphid (a louse-like plant parasite kept by ants as "domestic animal"). Both kinds of Ant are aggressive and double HP - one more reason why you should absolutely not attempt this quest alone if you are under level 40.
South of the Ant Nest, in the middle of the Wasteland, you will find Tyrants (lvl 35, passive) and Tyrant Kingpins (lvl 36, aggressive). They should not pose a major problem, but keep an eye on the aggressive Gigantiops ant groups who are living in the same area.
If you leave the Wasteland through the southern exit and then turn east you will soon arrive at the hill southwest of the Monster Race Track. At the bottom of the hill you will find Glass Jaguars (lvl 27, passive) and up on the top Silenos (lvl 30, passive). Watch out, the Skeletons hanging out with the Silenos are aggressive.
Horror Mist Rippers (lvl 27, aggressive) are to be be found in the outer fringes of the Cruma Marshlands. They are living together with highly aggressive lvl 29 Marsh Stakatos who can be quite a nuisance.
Also in the Dion area, on the upper level of the Execution Grounds fortifications, can be found Amber Basilisks (lvl 30, passive). They can stun, but as long as you stay away from the highly dangerous lvl 35 Hangman Trees they should not be a major problem.
In the Gorgon Flower Garden northeast of Giran you have to kill Turak Bugbears (lvl 31, passive) and Turak Bugbear Warriors (lvl 33, aggressive, double HP) until you get a bottle of Bugbear Blood.
6) When you have all the ingredients, return to Matild. She will prepare a Wish Potion for you that goes in your regular inventory, i.e. it can be sold or traded.
7) At the same time you get Matild's Orb that serves as a "certificate of friendship". This goes in your quest inventory and means that you don't have to kill the Secret Keeper Tree again (see step 2 and 3) if you want to repeat the quest. But first take the Wishing Potion. If you talk to Matild again and click on "I am gathering the ingredients", she will berate you for being too greedy.
8) When you click on "I want to take the Wish Potion", Matild presents you with four Tarot cards. You can choose between love, wealth, power and wisdom.
9) If you click on "I wish to be a loving person", Matild tells you to apply some crow's blood to your forehead and shake the wing of the fairy. The key word here is "wing" - after some chanting a Fairy of Love named Rupina will apear.
Talk to Rupina and she will reward you at random with a C-Grade Demon's Stocking Pattern, a Demon's Tunic Fabric, a Demon's Boots Fabric, a Demon's Gloves Fabric or a B-Grade Necklace of Blessing.
Alternatively three aggressive lvl 40 Succubi of Seduction might appear. When you kill them you may get nothing or a Forbidden Love Scroll that you can sell to the Dwarf Torai who stands at the southern end of the Death Pass in Giran Territory.
10) If you click on "I wish for 100 million adena", Matild tells you to shake a Timitran leaf. Here the key word is "leaf". Leaves are eaten by caterpillars, and before you can say "surprise" three aggressive lvl 50 Grima caterpillars will spawn.
Kill the Grima and you will either obtain nothing or a gold bar stamped with Duke Byron Ashton's seal that you can sell to Captain Alex, head of the Floran Village Militia. Or you might get either 10,000 adena, 900,000 adena or 100 million adena in cash.
If you are really lucky, no Grima appear and you will get 10,000 adena just like that.
11) If you click on "I wish to be a king!", Matild tells you to "put the crown of glory on your head". In fact you might get an Ancient Crown that is worth 500a in any NPC shop, or alternatively a Certificate of Royalty worth 5a. This is the most probable outcome.
Rarely, about once in 10 tries, different things could be happening. One is that the passive lvl 3 Imp Alexandro Sanches spawns. If you kill him you will get at random a Demon's Stocking Pattern, a Demon's Tunic Fabric, a Demon's Boots Fabric or a Demon's Gloves Fabric. An other possibility is that after you have killed Alexandro Sanches, the passive lvl 3 Goblin Bonaparterius shows up. Killing him will give you the same rewards. Or Bonaparterius will spawn and turn into the lvl 3 passive Orc Ramsebalius. Again the same rewards. If you are lucky (or unlucky, depending on your level), Ramsebalius will spawn and transform into the lvl 60 (!) aggressive Great Demon King. Killing that one will give you 1,406,956 exp or a whole Demon's Tunic, Demon's Stockings, Demon's Boots or Demon's Gloves.
12) If you click on "I wish to be the wisest person in the world", Matild tells you to "hit your head three times with a Sage's Staff". Three is the key: you will get three random Spellbooks, or the Amulet Pa'agrio's Heart. Or a Wisom Chest might appear. Talk to it, and you will also get at random three Spellbooks, Pa'agrio's Heart, a Musical Score - Theme of Love or a Musical Score - Theme of Battle. The Musical Scores are worth 250 adena in an NPC shop, or you can keep them and talk either to Melody Maestro Octavia in Dion or Melody Maestro Kantabilon in Heine. They can both be found in the Grocery. As long as you have a Score in your inventory, both will make you Echo Crystals for the respective Theme at the price of 200a per Crystal.
Without a Score you won't be able to buy an Echo Crystal.
13) When you have made your wish, you can talk to Matild again and tell her that you want to gather new ingredients. Then you will get the two recipes in your quest inventory again. Repeat from step 5).