Umbann, which is both the name of the city and the island, is the main trading post for Fui Ley and is inhabited almost purely by kobolds.
The city is split in two as all the residences, local stores, and important buildings are far up in the trees, the trading posts, ports, and inns are placed firmly on the ground and are medium-sized as opposed to the homes of the kobolds who live in them.
Throughout the whole island, people don't live on the jungle floor but rather in small balcony-like huts, placed directly on the huge jungle trees, encompassing the trunks in the safety of the treetop shade.
Particularly, there is a significantly popular shop by the coast, the Size is Everything shop, which only sells one kind of potion and one kind of mushroom. A size-reduction potion and a size enlargement mushroom. Their effects last 24 hours so the influx of people coming to buy the potion is constant at almost any time of the year.
People are very interested in the Kobold city of Umbann, and individuals who cannot be respectful are thrown out after they've paid for any damages they may have caused. By coin or by working to "replace" the supply of mushroom and potion ingredients they wasted. This works because the amount of mushroom and potion ingredients needed for the tourists and adventurers is growing considerably and bigger people have bigger hands to help gather it.
The potion, however, doesn't work anywhere but on the island as the spores from the trees mixed with the potion and mushroom is what makes the effect last so long. When too far from the trees or out at sea, the effects only last for a couple of minutes. That is, unless you have gathered the spores up and inhale them regularly along with either substance.