With Closed Door (Sealed), these serve as location limiters and prevent lower leveled characters completing high-level quests. Whereas sealed closed doors can prevent access based on quest flags and vocation, gates of expertise only check the character's level. Other items like Magic Forcefields (at Banuta and Demon Forge) and Energy Sparks (at Goroma) have been noted to have entry requirements as well.
If you do not meet the requirements to pass through the gate, you will see the green message "Only the worthy may pass". If you look at the door, it will tell you what the requirements are.
The Banuta Gate of Expertise for level 999 was tested during the 2009 Summer Test Server, and Mastro Daro, the player who walked in to the teleport proved that the teleport is only a sprite, nothing happens if you walk into it. He reached level 999 due to a bug which allowed you to gain absurd amounts of levels on the test server. Therefore it is not possible that Cipsoft deactivated the teleporter on the test server, as they had no idea that this bug existed. The teleport leads nowhere for the moment being, but it might change when people are close to level 999.
Generally, the more difficult the area or valuable the treasures behind the Gate of Expertise are the higher the level that is required.
You can stop within a Gate of Expertise and fight any monster that is behind it. It is impossible to lure or push a creature through a Gate of Expertise. This makes them useful for escaping creatures you cannot defeat. You may still inflict and receive damage through the gate, so it's not recommended to go afk at for example the entrance to the Water Elemental Cave since you may get killed.
List of Doors (incomplete)
- Level 8 - Thais Arena (here, only during Kingsday)
- Level 20 - Desert Dungeon Quest (here)
- Level 25 - Draconia Quest (here), Whiteflower Temple near the Banshee (here, can be bypassed from a second entrance)
- Level 30 - The Big Old One (on the way to Paradox Tower, here), Mintwallin (Devil Helmet Quest, here and here), Green Djinn Tower (here), Blue Djinn Tower (here), Cyclopolis (fourth floor, here), Magician Quarter Blue wing (Mad Scientists, here), Maze of Lost Souls (one in every wall here), Magician Quarter Research Centre (here), Pits of Inferno (on the way to the dragon lair, here).
- Level 32 - Circle Room Quest (here)
- Level 35 - Crusader Helmet Quest (here), Noble Armor Quest (here)
- Level 40 - Orc Fortress Quest (here), Darashia Dragon Lair (here), Koshei The Deathless Quest (here), Naginata Quest (here), Mad Mage Room Quest (here), Realm of Dreams Quest (here)
- Level 45 - The Outlaw Camp Quest (here)
- Level 50 - Black Knight room (here), Tiquanda Water Elemental Cave (here), Deeper Fibula Quest (here)
- Level 60 - Medusa Shield Quest (two doors here), Demona (here), Fire Axe Quest (here), Vandura Mountain (here), Magician Quarter Red wing (Ice Witches, here), The Queen of the Banshees Quest (here)
- Level 70 - Vampire Shield Quest (two doors here)
- Level 75 - The Ancient Tombs Quest
- Level 80 - Behemoth Quest (here), Medusa Cave under Talahu (here), The Pits of Inferno Quest (here), In Service of Yalahar Quest (here), Wrath of the Emperor Quest (here)
- Level 100 - Demon Helmet Quest (here), The Annihilator Quest (here), The Inquisition Quest
- Level 999 - dead-end teleporter (here)