More Than Meets the Eye
By Elmar
1) This one-time quest, which can be picked up a level 50, starts with Necromancer Hardin in his Private Academy, situated in a cave under the mountains encircling Dragon Valley. Hardin's Private Academy can be reached by Gatekeeper from Giran, Oren and Hunters Village or by turning east at the northern end of the Death Pass and then following the foothills until one comes to a forested valley.
Hardin will tell you about Transformations.
2) Then Hardin sends you to Magister Errickin in Hunters Village. To make the Stabilized Ectoplasm Hardin requires for his magic, Errickin needs raw Ectoplasm, which is - of course - obtained from ghosts. The Dark Elf tells you to go to the Forest of Mirrors east of Hunters Village and kill Forest of Mirrors Ghosts as well as Mirrors. (The "Mummy" on the dialogue screen is an obvious transliteration error for "Mirror").
3) Double HP Mirrors (lvl 49, passive) and three different kinds of Forest of Mirrors Ghost (lvl 46, 47 and 48, all aggressive) can be found to the east and west of the road. You get Ectoplasm from about every second mob killed, sometimes even 2 or 3 at a time.
4) When you have 35 bottles of Ectoplasm, return to Errickin. He will refine it into Stabilized Ectoplasm. Bring that to Hardin.
5) The Stabilized Ectoplasm will ensure that your inner self keeps its identity during a transformation. But you still need a spell, the so-called "Seal of Transformation", which has to be written down in a special Book of Seal resp. Sealbook. Magister Clayton in Dion can make an empty Book of Seal. Take Hardin's Instructions to Clayton.
6) Magister Clayton resides in the Dark Elf Guild in Dion. For creating an empty Book of Seal, he will ask you to hunt Glass Jaguars which can be found on the Plains of Dion. They will be dark blue to you at level 50.
The quest item acquisition rate is 100% and you need only 5. You will also be pestered by aggro Dire Wolves and Monster Eye Destroyers but they will all be around 20 levels below you, so this is not a problem.
8) When you have your 5 Glass Jaguar Crystals, return to Magister Clayton in Dion. He will make a Blank Sealbook for you. Take that to Hardin.
9) Hardin first gives you a concoction to drink he has made from the Stabilized Ectoplasm - which prepares you for taking on any transformation you want - then he writes the spell to transform into an Onyx Beast in the Blank Sealbook. You get to keep the Sealbook plus 67,550a for your help in Hardin's research.
The Transform Sealbook goes in your normal inventory. If you are not interested in becoming an Onyx Beast, you can sell it.
10) If you want to learn how to transform into a white leopard, however, go to the Ivory Tower and talk to Avant-Garde, the Transformation Wizard resp. Wizardess on the 2nd (Human) floor.
Then learn the skill to transform into an Onyx Beast. If you should unwisely have sold your Transform Sealbook, you can purchase a new one from Avant-Garde for 500,000a.
The Transform Skill, like any other skill, goes into your skillbook. Once you trigger it and change into an Onyx Beast, the regular skills will vanish and be replaced by the Transformation-specific skills, in this case Power Claw, an attack skill with a power of 1008 that needs 61 MP, and Fast Moving, which increases your speed by 50 percent (in my case from 147 to 213) for 15 seconds at an MP-cost of 61. Transform Dispel at the bottom is for turning back into your natural shape.
A Transformation regularly lasts for 30 minutes and has a reuse time of 4 hours. The reuse time also counts down when you are not logged in. You can use a different transformation, like for example a Golem Guardian or a Death Blader, immediately after the first transformation runs out, however.
This is a one-time quest, but it is not shared between main and subclass. If you want to use transformations on your subclass too, you must do the quest again with your character switched to sub.
See also:
[1] NCKorea Powerbook Transformation Know-How