Dwarves have a well-earned reputation as a supersticious and stern people, ensconced within citadels and cities of rock and magic. To outsiders, a dwarf's supersticion might make them look crazy. To dwarves, a supersticion usually means respect to their elders, ancestors, family, and to all the nature and world around them. To a stranger, they can seem untrusting and clannish, but to their friends and family, they are warm and caring, their halls filled with the sounds of laughter.
In the original Divinity War, their father deity, Moradin, was cursed. A curse so strong it bled through his divinity and effected all of his kin, all dwarves. A curse which would slowly deplete Moradin's life and strength, and which would slowly lead to all of the dwarves to become infertile. As such, all dwarves were fated to die, if not by Moradin's last sacrifice, abandoning his own divinity to create a ritual which would allow Dwarves to reproduce, creating their own kin by molding rock and earth, infusing their own vital energy into earth to create another dwarf.
As such, nowadays, all dwarves are born from earth, and to earth they will return once their energy runs out.
A dwarf lives anything between 200 and 500 years, depending on how many children they have and how many coparents each child have. However, having no children is seen as a vice, and after a certain age, such a dwarf will be labeled selfish and egotistical, and shunned from society.
Dwarves are slow to trust those outside their kin, but their wariness is not without reason. After all gods were killed, many races hunted dwarves to discover the secret of their reproduction ritual and twist it to their own benefits, by any means necessary. Although this hunt has never wielded any results and non-dwarves were never able to do anything even close to the ritual, disclosing it to other races is still seen as one of the biggest sins a dwarf can commit. Such a person might even be hunted down and considered an enemy of dwarves.
The reproduction ritual is instinct to all dwarves and has small particularities which vary according to the clan. Some of these are even written in their clan daggers, although no one outside of the clan can decipher what it means, as it mostly looks like nothing.
Even nowadays, although long dead and to many forgotten, almost all dwarves still pay respects to the All-Father, Moradin. From small rituals in his name to entire temples dedicated to him, each clan and culture does something different, but almost universally dwarves commemorate All-Father's Glory, a holiday that happens on first double crescent moon of each year, normally in the third week of the first month of Essalie, in which a ritual of melting down precious materials in his name is done by the moonlight.
A dwarf's life has plenty of small rituals scattered throughout, which makes them seem very supersticious. The dwarven language has many small sayings which works like prayers, like "blessed duty" right before starting working, "tink in the night" right before trying something new or traveling by a road you've never used before, or "no sprout in the walls" before meeting someone new. Besides that, there are also many rituals ingrained in their culture, from shorter ones of 2 to 10 seconds for everyday things and bigger ones for life events. These rituals may vary from clan to clan, but dwarves who grew up doing all of these rituals and saying all these prayers will be seen as supersticious to others.
However, that's not the only reason why dwarves are seen as supersticious. Many dwarves still fear that the curse will have side effects. All clans have some kind of strange ritual that is said to ward away the curse, and many bad things that happen to people who don't do these rituals are blamed on their "lack of warding". Dwarves also tend to believe in things like karma and luck, and many at least pay homage to Tymora to ward off bad luck.
Erach is a strange, beautiful city. Most people only know a few things about the dwarven capital: it's up the mountains, and the coffee there is great. But what they don't expect once they get to the city is how much magic and nature is ingrained in their everyday life. The waterfalls that come from the natural cavernous ceiling of the market, the divine lights that shine up the main streets at night, the constant low hum of music near the center of the city, the incredible landscape of all the broken islands near the magically locked castle of the royal family, the city is incredibly beautiful, bountiful and charming to all that visit.
However, the many rituals and unspoken rules of the city makes living in there difficult for those who didn't grew up with such customs. From stopping to pay respects to the flowered metal wall near The Mason's Pub to the almost city-wide lockdown to play luck games once a month, there are many strange aspects to the culture of the city that people are unfamiliar with that might make it more difficult to live there.
Even though the city is not just a dwarven citadel anymore, the city is clearly still dwarven dominant, and their customs, which also vary from clan to clan, encompass the whole city, on both a physical and social way. And since every clan has their own small quirks, it's still difficult for non-dwarves to understand what it means to live among dwarves. After all, not many people know what it means to grow with tales of your race being cursed with eternal death and misfortune.