Each of the elements has a small strength or weakness to other elements which encourages diversifying the creature composition of your team to see what synergies you can find when combining multiple elemental types.
Move sets for each element are also centered around a core functional theme, that gives them a unique play style. Elements also tend to favour certain buffs and debuffs which help provides further thematic strengths and weaknesses.
Fire moves provide more elemental damage than the other elements and also tend to get amplified when making repeated attacks. This make fire very quick at removing opponents so long as you avoid repeating attacks too often and becoming predictable as then your opponent can counter you.
Water is all about cleansing moves that remove effects from themselves and their targets. Often their stronger attacks provide themselves with negative side effects or their targets with positive ones that they must then be ready to remove.
Earth has hugely powerful moves that are slow and often get disabled for a number of turns making their damage very inconsistent. But, thanks to having very effective defense moves, they have a good chance to hold out until their large attacks are ready again.
Air uses very quick attacks which gives their opponents lots of chances to use defense moves, but air moves also reduce their opponent’s accuracy making them very difficult to hit. Additionally there are some very large and fast attacks which come with big negative effects and so are situational, often used as an early finishing strategy.
Life builds up over time using effects on itself and its targets instead of relying on direct damage. With access to healing and also a solid variety of counter based defense moves the aim of it is to survive attacks whilst consistently increasing in power.
Death is all about chaos. Where all other move types have fixed results the death element moves have a wide variety of possibilities and range of impact.
Every creature species is aligned to one primary element which gives them access to all the moves of that element as well as some neutral moves. Additionally, most creatures have a secondary element that provides access to a subset of the moves in that element, replacing some of the moves from the primary element. Mixing elements allows for some interesting synergies to arise. For example:
Water and earth make for good combos as the water moves ability to clear away negative traits from self, pair nicely with the earth elements large attacks that then get disabled for many turns.
A more specific example of a creature with Air as primary and Death as secondary elements can use the following stratagem Howling Charge (which is melle) does massive damage and is very fast, but causes Blood Lung trait which massively slows down attacks for the next two turns. Ideally the speed of Howling Charge allows for an immediate second attack. Attack move Ghost Walk is the follow up as it prevents the target from getting to use a defense move. Ideally this one-two combo finishes off the target in which case it is a very safe way to end an opponent as a pure Air based creature would be stuck on other moves that may be counters or healed against leaving this attacking creature slowed by Blood Lung. Additionally the defense move Drawback which buffs projectiles could be used before the howling charge to fake out the opponent and make them less likely to block the melle base attack.