It is located in Lorencia 114 124

Exchanges your 10 Rena for Archangel weapon +0+L+6 Exllent options for your character class (MG gets Staff)

Rena can be obtained from the boss in Tarkan Zaikan (Reg time 6h)

After the exchange, you will receive a box that must be opened with a key. 

The key drops in LostTower 1-7 from the Pouch of Blessing monster with a 25% chance

Pouch of Blessing appears randomly every 8 hours