There is a 30% chance to open a level 1 door and 90% chance to open a level 20 treasure chest. Requires 2 Thief Keys.
Base state  

Skill ID  27 
Level  1 
Cast Range  40 
Effect Point  1 
Effect Range  400 
Hit TIme  2500 
Icon  
Item Consume Count  2 
Item Consume ID  1661 
Magic Level  20 
MP Consume  19 
Operation Type  A1 
Reuse Delay  30000 
Target Type  UNLOCKABLE 
Unlock Level 1 There is a 30% chance to open a level 1 door and 90% chance to open a level 20 treasure chest. Requires 2 Thief Keys. 

Unlock Level 2 There is a 50% chance to open a level 1 door and 90% chance to open a level 24 treasure chest. Requires 2 Thief Keys. 

Unlock Level 3 There is a 75% chance to open a level 1 door and 90% chance to open a level 28 treasure chest. Requires 3 Thief Keys. 

Unlock Level 4 There is a 100% chance to open a level 1 door, a 5% chance to open a level 2 door, and 90% chance to open a level 32 treasure chest. Requires 3 Thief Keys. 

Unlock Level 5 There is a 100% chance to open a level 1 door, a 30% chance to open a level 2 door, and 90% chance to open a level 36 treasure chest. Requires 4 Thief Keys. 

Unlock Level 6 There is a 100% chance to open a level 1 door, a 75% chance to open a level 2 door, and 90% chance to open a level 40 treasure chest. Requires 5 Thief Keys. 

Unlock Level 7 There is a 100% chance to open a level 2 door, a 5% chance to open a level 3 door, and 90% chance to open a level 44 treasure chest. Requires 6 Thief Keys. 

Unlock Level 8 There is a 100% chance to open a level 2 door, a 30% chance to open a level 3 door, and 90% chance to open a level 48 treasure chest. Requires 7 Thief Keys. 

Unlock Level 9 There is a 100% chance to open a level 2 door, a 75% chance to open a level 3 door, and 90% chance to open a level 52 treasure chest. Requires 8 Thief Keys. 

Unlock Level 10 There is a 100% chance to open a door below level 3, and 90% chance to open a level 56 treasure chest. Requires 10 Thief Keys. 

Unlock Level 11 There is a 100% chance to open a door below level 3, and 90% chance to open a level 60 treasure chest. Requires 11 Thief Keys. 

Unlock Level 12 There is a 100% chance to open a door below level 3, and 90% chance to open a level 64 treasure chest. Requires 13 Thief Keys. 

Unlock Level 13 There is a 100% chance to open a door below level 3, and 90% chance to open a level 68 treasure chest. Requires 15 Thief Keys. 

Unlock Level 14 There is a 100% chance to open a door below level 3, and 90% chance to open alevel 72 treasure chest. Requires 17 Thief Keys. 