Alchemy can be done by first going to the Keep tab (found under the Castle Age banner), and clicking the Alchemy Tab. The Alchemy Tab keeps track of most of your alchemical components. Components that aren't listed on this page can also be found in the Town tab. Alchemical components can be used to create soldiers, equipment, magic, Generals, other alchemical components, and summon monsters. The alchemy tab is separated into three sections: Recipes, Summons, and Quests. Performing alchemy can also unlock Achievements.
No longer part of the game, it was obtained from several quests in the Undead Realm. Even though it was a consumable item, it was listed as an alchemy ingredient.
Monsters can drop the alchemy items needed to summon monsters, but the only way get summoning Orbs is through the quests mentioned above.
You may only have one of each summoning orb at a time (Keira, Gildamesh, etc.). If you repeat the quest that gives these orbs, it may appear that you received a second orb, however, you will have one in your inventory at a time. If you did the quest enough times to get five orb drops, but never summoned the appropriate monster five times, the quantity of orbs that you have will still be one.