Well, if it's just to kill time, then, here I go:
Water town (
Atlantis could be the name of its kind, couldn't it? Like Dungeon or Academy. Or maybe
Coral). All their units are immune to water/ice based spells, half of air based, although take double damage from fire/thunder and + 50% from earth.
Lv1 - tiger ray: a stingray coloured similar to a tiger, not that yellow, kind of blueish/greeny. It is a flyer unit which can sting a foe, poisoning it. It also cannot be retaliated. For an upgrade, comes the giant ray. Adds much of HP and defense, plus being now a large unit (maybe the unique lv1 large unit). Stats as they follow:
Tiger Ray:
Attack 5; Defense 2; Damage 2-3; HP 6; Speed 6; Initiative 8; Abilites: poisonous sting; flyer; non-retaliable attack.
Giant Ray:
Attack 5; Defense 5; Damage 2-3; HP 12; Speed 5; Initiative 8; Abilities: poisonous sting; flyer; non-retaliable attack; large unit.
Lv2 - mermaid: female fighters, swift and using tridents to fight. They can also deceive enemies with their beauty. Myriads, their upgrades, can sing during the battle, being able to cast some ailments on the foes or onto the allies, randomly. Stats as they follow:
Mermaid:
Attack 8; Defense 5; Damage 3-6; HP 16; Speed 7; Initiative 12; Abilities: long weapon (it attacks from 2 squares distant); hypnotize (20% chance to hypnotize when attacking - increases with Soldier's luck
).
Myriad:
Attack 10; Defense; 5; Damage 4-6; HP 21; Speed 8; Initiative 14; Abilities: long weapon; hypnotize; singer (active ability three times per battle, with the following possible effects on all allies OR all foes at once: good stats (regeneration: 10% of ally HP is recovered each of their turn - higher number of Myriads implies on time of duration of that effect ; happiness (stupid name): + 1 luck to all; protection: 10% magic resistance. Ailments: (terror: - 1 morale to all foes ; spectral: ranged attackers can miss with a 10% chance. Enemy spell casters cannot cast spells - this ailment should have 5% chance to happen only ; charm: enemies won't attack Myriads for a while - fixed number of turns, even when gathering 70997070767 zillions of them).
Lv3 - undine, another female like entity, will be a being made of blurry water, starry-like, hair waving graciously. A magical entity, with spells to cast. Magistral undines are much more powerful spellcasters, also being able to mix themselves to their ambiance (while fighting on shores or water) to disguise them while attacking foes. Stats as they follow:
Undine:
Attack 8; Defense 8; Damage 6-8; HP 20; SP 12; Speed 4; Initiative 10; Abilities: unsubstantial (take less damage from physical attacks, like - 20%), spell caster (casts: water barrier - enemies cannot pass through this barrier as long as it lasts. It always last 2 of undine's turn and costs 8 SP ; cyclon - with area effect (3x3), does water damage on all foes and can move them to the next square on clockwise matter within that area. It won't work with large fiends or any foe in the middle of the area ; Cleansing).
Magistral undine:
Attack 8; Defense 8; Damage 8; HP 22; SP 24; Speed 5; Initiative 12; Abilities: unsubstantial, spell caster, melt around (disguise during 2 turns, completely disappearing from enemy's view and cannot be targeted by physical attacks, but can be affected, severely, by magic if they happen to be on an area which an upcoming spell hits. It can cast spells during their disguise, or do any other action).
Lv4 - seahorse: being mounted by a merman or something like that, the sea horse is a fast, ranged flying unit, with a great charging melee attack too, since the mounted warrior strikes with his weapon, while the seahorse breaths an ice ball. Seaknight are pretty much stronger in attack, defense, HP and speed. Stats as they follow:
Seahorse:
Attack 12; Defense 10; Damage 12 - 15; HP 60; Speed 6; Initiative 11; Shots 6; Abilities: flyer, water-based ranged attack, no melee penalty, charging attack, large unit.
Seaknight:
Attack 15; Defense 14; Damage 16-20; HP 70; Speed 7; Initiative 13 ; Shots 10; Abilities: same as above + enraged.
Lv5 - triton: a potential hero of the seas, armoured with strong arms and tail, wielding a piercing harpoon which it throws onto the enemies. Sentinel is an elite version of triton itself, but it has an ability to control some of the sea beasts, mounting on them, mixing some properties equaling in number of sentinels, leaving the rest of those non-used units as other stack. At the end of the battle, sentinels will dismount.
Triton:
Attack 13; Defense 18; Damage 14-17; HP 50; Speed 5; Initiative 10; Shots 8; Abilities: ranged, no melee penalty, ignores defense; breaks defense (each hit will drop 2 of target's defense); tail strike (this ability does only 1/5 of normal damage and will push away the target, even being a large one. They are pushed 1 square away only).
Sentinel
Attack 15; Defense 20; Damage 14-17; HP 65; Speed 6; Initiative 10; Shots 6; Abilities: same as above + mount (this unit will mount only on: giant ray (bonus: Attack + 2; HP + 10; Speed - 1; Initiative + 2; Abilities: loses ranged ability, loses tail strike, gains large unit, gains double strike - one attack is with Sentinel's damage, the other with giant ray's damage - poisonous hit) ; Sea serpent/Marine serpent (bonus: when mounting sea serpents - Attack + 10; Defense + 5; HP + 60; Speed + 1; Initiative + 1; Abilities: loses tail strike, gains long large unit, snake strike retaliation (snake strike attack will only affect on retaliating, with Sea serpent's damage for it. When mounting marine serpents - Attack + 10; Defense + 10; HP + 100; Speed + 2; Initiative + 3; Abilities: loses tail strike, gains long large unit, snake strike retaliation, shocking barbs - note that sentinels will never lose their ranged ability when mounting sea serpents or marine serpents)).
Lv6 - sea serpent: a giant foe, with a long body (3x1) but thin, has incredibly ability to smash quiet fast any other unit. It has a snake-like bite, so fast that it will attack anything before it attacks, and anything that comes close. Marine serpents are armoured by the sea lords to increase the power of their electrical barbs. With their immense body, small units can be bind, being unable to move.
Sea serpent:
Attack 19; Defense 15; Damage 26-32; HP: 130; Speed 7; Initiative 9; Abilities: large and long unit (3x1), snake strike (this unit will retaliate before being hurt - doesn't apply over other attacking sea serpent), caution (active ability taken when this unit defends, it will attack any other enemy unit that gets closer - on a side square - even when just passing by it).
Marine serpent:
Attack 21; Defense 20; Damage 30-32; HP:150; Speed 8; Initiative 8; Abilities: same as above + binding body (it will enclosure small units, being able to attack just this unit. Trapped unit will be able just to attack the marine serpent which will retaliate just this unit (multiple times, if the enemy has great initiative), and won't perform caution either. This trapped unit will do only half of normal damage and won't be able to perform spells. This ability has a 50% to fail when the Marine serpent goes for it losing its turn), shocking barbs (when a unit attacks Marine serpents, it gets 4 electrical damage per marine serpent plus 10% of chance of being stunned, losing 50% of its initiative for the next turn).
Lv7 - kraken
Coming soon...now I have to go home.
. Comming soon, my water town, ice town, earth town (not sylvan 
