Runecraft

Runecraft is the original magical art used by the dwarves long before the introduction of Rank Magic.

Background
Two hundred years ago, runecraft was the traditional art practiced by the dwarves of the Dwarf Kingdom. However, after the Demon God Unrest, the art has become nearly extinct. It further declines into oblivion when younger generations of dwarves begin abandoning its use in favor of the more practical and effective Rank Magic.

Mechanics
Runecraft is the art of inscribing magical letters onto objects. When a rune is carefully engraved, on an object it enchants the object. The amount of magic inscribed in an object depends on time it takes to inscribe a rune.

There are 50 lesser runes, 25 middle runes, 10 upper runes, and 5 top runes, for a total of 90 runes overall. That said, many of them have been lost, and only a few are left. Exactly how many secret and divine-class runes there are is the stuff of legends. According to the dwarven runesmiths, it is not possible to carve runes and place enchantment on the same object. Runes are characters imbued with mana. Thus carved runes and enchantments are mutually repulsive. If a powerful magic caster tries an enchantment, the runes will distort.

Runes apparently are abandoned by the dwarves due to several disadvantages. Compared to Rank Magic, which could enchant an item in a near instant, runes require time, thus using it in full production is not cost-effective. In addition, only runesmiths are able to create and utilize runes, and the number of dwarves capable of becoming runesmiths is said to be even less than those capable of becoming magic casters. However, runes possess advantages not found in the Rank Magic system, one of them being that runes hardly require any material cost.

Though the origins of runecraft are lost to the surviving runesmiths. Ainz Ooal Gown theorizes that runecraft may have originated from YGGDRASIL, and that perhaps the runecraft system was never discovered by players due to its obscurity and machinations of the developers.

Trivia

 * Some runes used by the dwarves are recognized to be the same as the runes from Satoru Suzuki's world.
 * The runesmiths of the Dwarf Kingdom stated that only a number of six runes has ever been known to be successfully embedded into a single weapon during the peak of the craft.