Hello;

Question about card:

If it is attached to a character, does it automatically become Attachment for other card's effect purpose, like:

???

Thanks;

From one hand it is being attached.

On the other hand it does not write that it becomes Attachment .

Yes. When a card becomes attached to another, it automatically gains the 'attachment' subtype.

So, it'll count toward the City.

IMHO this card (City) should be unique.