Equipment- All, minus plate
At 1st level, all Elemental Warriors begin as Elemental initiates. They have a base AC of 10 and have a maximum AC of 16. They also begin with the same to-hit bonus and combat abilities as a first level fighter, but have less health and lesser equipment.
Elemental Initiates can speak to or commune with elemental spirits as they are present in the setting, but do not get a bonus to their reaction roll with them as a shaman or priest would. Also, elemental initiates get +1 to save against all saving throws closely tied to the four elements, such as dragons breath and petrification.
When the Elemental Initiate reaches 2nd level, they must choose one of the elements to champion and master, abandoning the others except for the base abilities earned at first level.
Warrior of Fire
The moment the Elemental Warrior becomes a Warrior of Fire, he may start fires by holding and blowing on dry tinder up to his mouth at any time, effectively acting as a candle-flame cantrip. He also gains +1 to all saves against fire based spells or breath attacks; and gains an additional +1 to fire-based saves every level from now on.
Once per day per level, the Warrior of Fire may engulf his blade in flames with a strike, dealing an additional +1d6 fire damage. This must be called before the attack is rolled, and on a miss the flames harmlessly singe the target. Even on a miss, this attack could ignite extremely dry or flammable material, such as a creature covered in lantern oil or an animated scarecrow.
At 10th level the Warrior of Fire may become a living flame once per day. In this form, he can only be harmed by magic weapons or spells and looks like a giant fire. This giant fire can leap and crawl across the ground even without fuel, but will become weak without it. It can also shoot 1d6 damage sparks at anyone within throwing distance. By consuming flammable objects the living flame may grow larger and move faster. The Warrior of Fire can keep the form going for 1 turn. If the fire is extinguished the Warrior of Fire will reappear in the embers of the flame unconscious.
Warrior of Water
Elemental Warriors of Water can identify if a source of water is safe to drink or poisoned by running their fingers through it. They can also identify other liquids like wine by making a save and adding their level to the roll. On a failure, they cannot be sure or not if the liquid is safe. They get +1 to all saves involving water every level from now on.
Warriors of Water can hold their breath underwater for a number of exploration turns equal to their level. Also, Water Warriors can create a spear, arrow, or shield made of ice that has a one time to-hit or AC bonus equal to their level, once per day.
At 10th level the Warrior of Water can become living water. In this form they can either stay still and imitate a regular body of water, drip through cracks and crevices, or move in a great torrent of water like a crashing wave. You are also immune to non-magical weapons. Instead of attacking, the Warrior of Water could attempt to drown foes or skirt away allies. Enemies only get a save to avoid being knocked over or swept away if they are very large or have a strength modifier of +2 or better. They can sustain their form for as long as they wish, but if too much of their liquid is separated they will be trapped in elemental form until they rejoin.
Warrior of Earth
Elemental Warriors of Earth get to wear platemail and have their maximum AC raised to 18 due to their connection to stone and earth. They get +1 to saves involving petrification, cave-ins, earthquakes, mudslides, and similar Earthy hazards every level.
By stomping their foot, the Warrior of Earth can cause stalactites and shards of stone to jut into their enemies. The Earth Warrior must make an attack roll, with their level as the bonus to hit, against the enemy's AC and on a successful hit deals 1d8 damage. The Earth Warrior can also do this on softer ground like gravel or dirt, but this can only open a pit beneath the enemy to trap or distract them. They can do this once per day per level.
At 10th level, the Warrior of Earth can transform into an Earth golem. In this form they have 20 AC, stone fists that deal 1d10 damage, and always go last in the initiative order. They also have tremendous strength, and could easily break through thin stone walls or thick wooden ones. Their incredible weight means most wooden bridges or floors couldn't support their weight. They can stay in this form for up to 1 exploration turn.
Warrior of Air
The warriors with the power of Air is closely attuned to the secrets of the winds. They can hear a whisper spoken within 10ft per level as the wind carries it to their ear. Also, Warriors of Air get +1 to saves to avoid all air related saves, including toxic gases or lighting strikes, every level.
Warriors of Air can redirect missed projectiles like arrows back at the targets again for a second attack roll, and can do this once per day per level. These can be spent in advance, such as granting each member of a squad a single magically empowered arrow for a single devastating volley. Warriors of Air can also give up their combat round to give themselves or any of their allies within hearing distance a +1 AC bonus against all incoming attacks by whistling a shield of wind.
At 10th level, the Warrior of Air can become living wind. This specter is almost invisible and can only be harmed by magic weapons and spells. It is a low flying wind that can only travel near to the ground, but can “climb” up sheer surfaces depending on weather conditions and wind chimes to act as jumping points. The specter can only interact with people or objects by whispering in their ear or with a subtle gust of wind that can blow out candles or shift the pages of an already open book. The air-form must stay mostly together but can pass through objects that are open to the wind; something like a heavy curtain could block them just as it could block the wind.