Here is the corresponding levels on both sides.
--------------------------------
Level 1 - Level 15 [system] = Level 1 Adventurer [Falna]
Level 16 - Level 30 = Level 2 Adventurer
Level 31 - Level 40 = Level 3 Adventurer
Level 41 - Level 50 = Level 4 Adventurer
Level 51 - Level 60 = Level 5 Adventurer
Level 61 - Level 70 = Level 6 Adventurer
Level 71 - Level 80 = Level 7 Adventurer
Level 81 - Level 90 = Level 8 Adventurer
Level 91 - Level 99 = Level 9 Adventurer
Level 100 = Level 10 Adventurer
---------------------------------
Will also update the corresponding stat points here later :)