The Illusion Enchanter can be found in Prontera at (prontera 91, 115). You will get a short story the first time you speak with her.

Each item can be enchanted twice at the cost of 5  Illusion Stones per try. You can only enchant Illusion items.

You can also reroll a single enchant at the cost of 20 Illusion Stones per try.

Depending on the item type, you will get different enchants.

The Illusion Enchanter will reset both of your enchants for a cost. Before resetting the enchants, the item must be fully enchanted first.

Depending on the option you choose, it has a chance of failure which will end up breaking the item. It is recommended to pay the full price to avoid this situation.

Despite the regular Illusion enchanting system having weapon enchants, Illusion level 4 weapons don't share the same options.

Aside from  Illusion Sharpened Legbone of Ghoul [2], every other Illusion Dungeon weapon can be enchanted through  Resonance Stone of Dusk (physical) or  Resonance Stone of Dawn (magic).

The two stones can be purchased from the Illusion Merchant NPC (prontera 88, 113).

Each single stone costs either 2,000,000 zeny or 10  Illusion Stone.

Using a stone (double click the stone to activate it) will open up an enchanting window that will list every Illusion Level 4 Weapon on your inventory. Confirming the enchant will consume the stone and imbue the weapon with 4 random line enchants.

There is no chance of breaking, damaging, losing refines or cards on your weapon. You can overwrite the enchants on your weapon by using another stone.