Every Metin2 character has a storeroom, and it is account-bounded. That means all characters on the account share it, so an item you store on one character is reachable from the others. You open it through the Storekeeper NPC.
The Storekeeper
The wiki lists the Storekeeper in every major town: Joan, Bokjung and Songpa; Pyungmoo, Bakra and Daeyami; Yongan, Yayang and Miryang; and Cape Dragon Fire, Dong Gwang Plain and Bazaar. The NPC does four things. For 500 Yang he opens 45 inventory fields. He exchanges Yang for Won and back again. He sells Silver Bars and Gold Bars. And he holds the quests at levels 6, 30 and 57: The Blacksmith's mission, Helping the Storekeeper and Get Frog's Legs.
Opening more space
- The base offer is 500 Yang for 45 inventory fields.
- You can unlock 90 more fields by using a Storage Chest.
- The Item Shop storeroom is a separate thing. It holds items bought from the cash shop, starts at 225 fields across 5 pages, and cannot be extended.
- The Item Shop storeroom requires the same password you use on your regular storeroom.
Your default storeroom password is 000000, and you have to change it the first time you open the storeroom. If you forget it, you can reset it to 000000 from the gearwheel in your launcher on the account list. That takes you to the homepage, where you press Storekeeper. An email confirms the reset, and you get back in once you open the link in it.
The password bonus
Changing your storeroom password gives you a bonus that applies to every character on the account. A status icon appears in the upper left corner, the buff lasts 90 days, and each new password rolls a fresh random bonus. The wiki lists the possible bonuses as Max HP +1 percent, Defence +20, Strength against monsters +3 percent and EXP +5 percent.
Why the password trick is worth using
It costs nothing but a password change and it applies account-wide, which is unusual in Metin2 where most bonuses are tied to a single character. Because the bonus rerolls every time you change the password, you can keep the 90 day buff topped up without spending Yang.
FAQ
Q: Is the storeroom shared between my characters?
A: Yes. The wiki says it is account-bounded, which means it can be accessed and shared amongst all characters on that account.
Q: Where do items I buy from the Item Shop end up?
A: In the Item Shop Storeroom, which you open from a button in your inventory. It starts at 225 fields and cannot be extended.
Q: Do I pay for the storage bonus?
A: No. It comes from changing your storeroom password, not from buying an item.
Sources
Metin2 Wiki: Storekeeper (locations, the 500 Yang fee, the password rules and the storage bonus)
Metin2 Wiki: User Interface (the Item Shop storeroom button and the storeroom notes)