Fire magic example tree.
Fire, unlike magma carries no weight. It is the transition of stored energy (Fuel) into another form of energy (Heat/light). When the fuel runs out so too does the effect. Fire, is a powerful servant... but when it becomes the master destruction awaits.
 

1 Point fire magic.

  
Fire bolt
(Ethereal creation)
 A flung flaming projectile from the caster, its very simple and weak. Though it possesses no mass when thrown it will hit something like a fiery baseball, then precede to ignite and burn what it comes in contact with. Once it leaves the hand of the caster it is no longer solid and will burst into flames when it hits anything including shields and swords.
Ignite
(Bless/Curse)
All characters in this system are believe to have some level of natural energy this spell just turns it against them. The caster writes the spell on a piece of paper (A hard thing for most fire users to do.) Then attaches it to the target. For as long as the paper survives the target burns with intensity equal to their natural energy. The higher their natural energy the more damage the spell does. The target can resist equal to their willpower.
Fire elemental
(Summon Elemental Spirit)

Tiny scampering creatures. From some nightmare or another begin leaping from nearby fires upon the casting of this spell. The more fire around the more creatures are generated. As they run the ignite a trail of fire behind them criss crossing the battlefield taking winding paths to the target. When they hit something (Obstruction, other fire, other magic.) They explode into a tiny fiery mass causing more flaming destruction.
Flare
(Ethereal creation)
 Something that burns twice as bright burns half as long. By increasing the intensity of a fire you increase its fuel consumption. This spell reduces the length of a fire bolt to a mere fraction of a second, in return the firebolt becomes so bright and heat intensive that it can burn through almost anything that isn't fire resistant.

2 Point fire magic.

  
A sphere of magic that's thrown at the target. It explodes on impact in a rippling teleportational wave of heat. The fire is real and fueled by reality sources not mana once the sphere explodes and thus will continue to burn until extinguished or out of fuel.
Fire bomb
(Summon element)
This spell alone can sum up most of the fire tree, its a ball of fire created by the casters natural energy and willpower and thrown. TO hit whatever it does with an explosive fire effect. Its easy to cast and perhaps the most common fire spell used due to its balance of power and strength.
Fire ball
(Ethereal creation)
The touched being is elevated above themselves, filled with a powerful raging calm which protects them from fear and other curses. Though they are without fear they still have their sense about them and still feel pain. Their willpower is doubled, and the casters willpower is added to theirs making any attacks that use willpower as a base exceptionally strong.
Courage
(Bless/Curse)
 

3 Point fire magic.

  
Intensity flare
(Summon element)
 The caster need only point and speak a phrase or two the object that they picture in their mind (Not character but object on the battlefield.) Becomes fuel for the most intense fire spell. Anything can fuel this reaction. The largest he chosen object the brighter and larger the flare. (No the ground is NOT a target.) When the flare is gone all that remains is the subtle smell of the burn target and an empty space where it was. Anything near the target will have been burnt badly.
Raging fire
(Summon Elemental Spirit)
With the caster as a center point a fire spreads out like a ripple spreading as far as their willpower with the intensity of their natural energy. As the fire rippled expands it triggers more ripples off the elemental spirits nearby creating waves of fire sweeping around the battlefield.
 

4 Point fire magic.

  
The sky darkens, natural animals know what's coming... from the dark sky flaming spheres the size of basket balls begin to fall. When they hit something they explode into a spreading fire. The rain increases with intensity for each passing moment until these spheres are falling as commonly as rain drops. The rain continues for as long as the casters natural energy will allow and when finished will leave the entire battlefield ablaze.
Burning rain
(Summon element)