Warp to Aldebaran and head to the Alchemist Guild (/navi aldebaran 68/54) or (@jump 68 54) on the bottom left of the map.
Go downstairs into the basement. Head to the first portal on the left side (/navi alde_alche 145/10) and talk to Mit Hocram. He will tell you that you need to find his students.
Head straight south (/navi alde_alche 89/65) and enter the room. Talk to Zitis Curium to start the first quest and bring her the required items. You will need:
Outside of Zitis room, head to the bottom left portal (/navi alde_alche 49/77), enter the room. You will find Mit's second student Aleph-Nos Relic, he will test Twilight Alchemy II on you.You will need:
200 Medicine Bowl
200 Empty Test Tube
200 Witched Starsand
200 White Potion
1 Condensed Potion Creation Guide
When you are done collecting all the items, Aleph will let you use Twilight Alchemy II. If you are successful, you can head to Mit's last student.
Head to the portal on the upper right side (/navi alde_alche 129/103). You will find Dredaw Reli, Mit's third student. With him you will perform the last Twilight. You will need:
200 Medicine Bowl
200 Empty Bottle
100 Empty Test Tube
50 Immortal Heart
50 Fabric
50 Alcohol
500 Stem
500 Poison Spore
1 Bottle Grenade Guide
1 Acid Bottle Creation Guide
1 Alcohol Coat Creation Guide
When you collected all items, you will cast with him Twilight Alchemy III. On success, you can now return to Mit.
Return to Mit Hocram. He managed to create a new skill, Twilight Alchemy IV. He is excited to try it out with you. You will need:
200 Medicine Bowl
200 Empty Potion Bottle
200 Blue Herb
200 Scell
With that last cast, you can now use Twilight Alchemy IV! Congratulations!