The nature of spells

I'm having trouble thinking of how to imagine spells in my world. What I'm currently going with is that they're sort of semi-sentient, kinda like they're described in the first two Discworld books by Terry Pratchett, and that the magic that a mage specialises in becomes greedy, and sorta cordons off an area of their mana pool that only it can use. I also imagine that spells granted by deities are scary enough that they get their own pool custom made, cause the signature magic is too greedy to give access to their bit of the pool, but too terrified to force the divine spells to swim in the much smaller area that they left for the universal spells. I also imagine that the use of spells sort of digs at the wall of their pool, slowly expanding it, and the signature magic always steals the area that eventually reaches the eternal spring of mana, allowing for the no-cost state I mention in the thread about my magic system in general. The divine spells may or may not also have an eternal spring that their pool could expand to, but most mages who have divine spells rarely use them, so most of the time their pool doesn't expand much.

 

I see it that the universal and signature spells are in the same pool, but when you develop a signature magic, it sort of builds a wall blocking some of the pool off from the universal spells, taking up the majority of the pool, because it's greedy. The divine spells get their own separate pool, cause the signature ones are too greedy to share but too terrified to make the divine spells use the small area that was left for the universal spells.

The pools are an internal thing for each mage, like typical mana pools, but the semi-sentience of the spells allows for it to be imagined as an actual pool.

As for the uber powerful, each spell is only so strong, the digging away at the edges of the pool just allows for spells with larger mana costs to be cast, or more castings of weaker spells. The stronger the spell, the more effective its digging tool. The signature spells eventually find a spring of endless mana, making the mage able to regain mana faster than they can expend it, but because of the wall that the signature spells made, the universal spells can't enjoy it. Universal spells are all the weakest spells of their magic type, so they can't dig very fast. There are rare exceptions, but they always require magical fuels cause the universal pool could never get big enough for them.

 

The separate pool for the divine spells is also partly because the divine ones are nice enough to not want to terrify the other spells, as any decent deity would while among mortals.