Im not a big fan of hard magic systems, and with time i've developed a little disdain for them. This is mainly because i feel hard magic systems make things in narratives sort of predictable, and after a while a system that follows the same rules ends up getting boring, because of this constrains. Im not saying soft magic systems suck and they are a blight upon literature, excelent writers like Hirohiko Araki and Brandon Sanderson can make this systems work extremely well without them getting boring, but more often than not i end up prefering the whimsical unpredictable effects of a soft magic system.
One of my favorite magic systems of all time has, actually, no single writer behind it. Historical myths and lore are based upon a soft magic system. A soft magic system based on metaphors and the exaggeration of concepts. In ancient myths, if a god jizzed the sea, a goddess was born out of it, its sort of a metaphor to represent qualities of said godess. For example, in the myth of Prometheus, life force and sustain is represented by fire, and Prometheus literally creates humanity (or society) by giving them fire. According to norse mythology, Loki and Angrboda gave birth to Fenrir, a god and a giant gave birth to a wolf, which makes no fucking sense if we think of it with a mindset based on conventional rules of life, BUT in this particular myth, the offspring of these two beings of chaos, creates another being of chaos, a wolf, because the wolf is an icon of power, Fenrir is the embodiment of Chaotic Power, this is why he grew rapidly and had to be bound with magic. In Aztec mythology, a god warned Hutzilopochtli, while he was still in the womb of his mother, that his sister Coyolxahuqui was on her way to kill him. Thanks to this, Huitzilopochtli used magic to be born fully grown and armed and defeated his sister. There is no logical explanation to how this kind of magic works, its just a soft magic system, and moreover, Coyolxahuqui's remains became the moon and Huitzilopochtli became one of the sun gods, always defeating the moon.
This is the kind of system that governs the supernatural in the sea of fog. Conventional rules of life apply in the same way as in our world. But when magic gets involved, the result of it is always tied to metaphors and the transposition of mundane (yet linked) concepts to achieve the impossible (like a pigeon impregnating a woman).
In a world where magic has no specific rules, this discipline is in constant development. The vastness, hostility and unchartability of the Sea of Fog forces its inhabitants to study magic in close circles, with oral tradition being the only way to transmit knowledge accross long distances. This means that the study of spells and incantations is often limited to a single area or group of people, and diferent peoples have diferent breakthrougs and knowledge.
Mages and wizards lock themselves in towers trying to unravel the mysteries of magic, but like with Sisyphus, their task may be considered futile by some, as in the end, the knowledge they aquire is lost when they die. But wizards exist because even after knowing all of this, they still are passionate about the process behind the learning and experimentation, sometimes even losing their sanities in the process.
Magic can be performed by anyone, and even sometimes by accident with no intention or doer behind it. Supernatural conditions have to be met for magic to happen, often involving acts, creatures or objects closely related to magic or divinity. As a simple explanation, if a man picks up clay and creates a little person out of it, nothing may happen, but if a god does it and infuses it with its power, he may give it life. And if a normal man picks up god blood and adds it to the clay, the clay figures may be infused with life.
There is no strict limitation to the power of magic and there is also no concrete way of knowing how powerful will a spell or occurence be.
This may lead to some "David vs Goliath" scenarios where massive threats are defeated by simple occurences, thanks to magic and how reality works. This is not common, however.