The elementals are the extra-dimensional beings that can be seen in other dimensions. Hydron is one of the elementals and is the master of water. Magnum is another elemental and he is the one that is responsible for manipulating different earth and rocks that are available. Zephyr is known to be the mistress of the winds and she is known to be very evil.
Hellfire is also another being who is known for having the ability to generate fires. The elementals are important because they have actually become immortal due to the different forces that are at work in this world. They have been available in this world even before Atlantis first started.
The elementals in Spider-man: Far from home are inspired by Spider-man’s villains (Mysterio and his crew). The elementals do not have any form of characterization. These humanoid creatures are composed of air, water, fire, and earth. As they manifested on Earth, they battled Earth 833’s greatest defences.
The elementals include: Earth Elemental = Sandman Water Elemental = Hydro-Man Air Elemental = Cyclone Fire Elemental = Molten Man (said to be the most powerful- it increases in size as it consumes metals). Hope you find this helpful.