Unique uniques spawn RANDOMLY at the player's location when enough mobs are killed in a certain location. These uniques drop skill point scrolls (confirmed) give decent exp (confirmed) and possibly drop silk scrolls (unconfirmed) AND TAKE A WHILE TO KILL (confirmed with Crossbow Extreme sun +7 xbow and 3 level higher rogue..)
Alchemy material no longer drops (which should reduce the "necessity" to use a bot for the pet-filter function). Alchemy tablets and the required items to make them into stones can be found in the special NPC seller in Donwhang.
Titans have been removed from the server