The uMon Corporation has added a "rock paper scissors" system of Elemental typings to their various fighting mons, to enhance the tactical complexity of the sport. (And, no doubt, to require people to assemble teams with complementary elemental types for serious competition.) While many mons do have obvious thematic affinity in their design for some element or another, and may include special hardware to support that (e.g. the ability to shoot jets of water), elemental weaknesses and resistances are largely artificial. The physical effect of a mon shooting a jet of water from a water-based elemental attack is likely to be little more than knocking small opponents over. However, uMon's elemental typing system would cause a mon struck by this attack to suffer some greater damage - at a minimum, what would be imposed by the natural damage of the attack, but potentially much more, if there was a type weakness. Additional elemental damage is inflicted by the victim's body on itself "in software" as it were, thanks to the physical changes a mon undergoes as part of becoming a battle mon.

Mons other than uMon-sanctioned sport mons (e.g. utility mons) do not participate in this Elemental typing system, and are "typeless." Typeless mons have no type weaknesses, and take the minimum (natural) damage from all typed attacks. Of course, some elemental attacks, like those involving large amounts of fire, for example, can still be rather damaging to typeless mons. Typeless mons are also affected normally by the typeless attacks (kicks, punches, bites, etc) that many mons possess (including sport mons.) However, many typeless mons made for utilitarian purposes like construction or security are very durable. On the other hand, typeless mons aren't normally equipped to inflict elemental attacks either. Although they are not permitted in sanctioned events, Typeless mons - usually modified utility or pet mons - are not particularly unusual on nonsanc teams.

Rock

Associated themes: geological features, non-crystalline minerals and rocks (no kidding), mountainous regions and their inhabitants, ceramics and stone materials.

Aether

Associated themes: natural and otherwise non-theurgic magic not more closely associated with other elements, psychic powers, ESP, telekinesis/psychokinesis, impersonal spiritual powers, Qi.

Metal

Associated themes: Metals, machinery, robots, armor, tools and weapons, artificiality

Wood

Associated themes: Forest and its products, plants generally, fungi, plant-associated mythological creatures and cryptids.

Fire

Associated themes: Fire, high temperatures, rage, lava, volcanism, smithy

Sky

Associated themes: Birds, sound, the physical heavens, the daytime sky especially, clouds, flying creatures, aircraft, light

Earth

Associated themes: The earth and soil, terrestrial animals and powers, earth spirits, mud, dirt, clay, archaeology.

Ocean

Associated themes: Water, aquatic creatures, the sea, seafaring, island and maritime cultures, the Golden Age of Piracy, rivers, lakes.

Phantasm

Associated themes: illusion and stage magic, hallucination, trickery, ghosts and apparitions, mystery lights and UFOs.

Holy

Associated themes: benevolent personal spiritual powers, sacred things, religion (not limited to themes of Abrahamic Monotheism, however), order, lawfulness, celestial creatures in mythology (not necessarily benevolent), good.

Underworld

Associated themes: malevolent personal spiritual powers, unholy or deconsecrated places and things, chthonic creatures (not necessarily malevolent) in mythology, the undead, evil, darkness.

Nymph

Associated themes: neutral personal spiritual powers, nature-associated mythological figures, the fae / fairies, shamanistic or animist religion, nature personifications, benign trickery and humor, disorderly and chaotic natures.

Crystal

Associated themes: Crystals (no, really?), crystalline minerals, glass and transparent things, gems and jewelry.

Lightning

Associated themes: electricity, thunder and violent weather, flashing lights and explosions.

Vapor

Associated themes: vapors, poisons, immateriality or subtlety, gases, humidity and swamps.

Ice

Associated themes: cold, snow, winter weather, polar phenomena, animals, and peoples, freezing.