ITT: Veeky Forums makes a magic system

ITT: Veeky Forums makes a magic system.
I'll start.
Magic is not linked to the users itself, but rather to objects.

These objects are relatively easily created, but require materials harvested from the bodies of innately magical creatures.

The art of creating and using magic items is collectively known as "objectification".

if magical objects for a spell recipe are used in wrong proportions, a dangerous reaction can occur causing wild-magic like effects.

top kek. 7th level objectifier; master of slaying no-fun-demons.

The only innately magical thing in the Human body is their youth, so spells can be made more powerful or long lasting at the expense of shortening the users life span.
Because of this, wizards look much older than they actually are

This is getting NSFW preeetty fast

In this context, would Wizards use parts of their body to create objects? Like, a guy yanks out a tooth and ages 5 years as it's incorporated into the magicbox?

Every wizard creates their own magic source, a Heart, from the organic materials of innately magical creatures - bones, hair, flesh, blood, teeth, etc. Wizards use their very lives to empower their magic, some spells simply exhaust can be recovered from, some are permanently damaging. Spells to prolong life are paradoxical and result in undeath.

People are inclined to distrust young wizards, as that means they're inexperienced at best and grave robbers or organ thieves at worst.

Sufficiently old magic items, or those exposed to enough wild magic might spontaneously develop sentience and humanoid features like eyes, mouths, hands, feet, etc. If made from the parts of a magical creature, they might develop some of their features as well.

These objects usually come as some sort of a puzzle box, or wands with sliding elements - manipulating them changes the nature of the spell.

Clerics of this universe are actually extremely well-seasoned hunter-gatherers, who spend their entire training sacrificing enough plunder to their patron deity, who, given enough devotion, produces a great artifact that channels saintly magic and is completely linked with the user. Losing it causes the cleric to also start siphoning away the magic he has - his youth. Disarming a cleric for a sufficiently long time turns him into dust. Clerics of conflicting alignments get great boons from their church and deity if they manage to bring another cleric's weapon and sacrifice it on the altar. Each great deity has a main, capital altar of its own, and great ceremonies are held for sacrificing weapons of high-ranking enemy clerics.

to create a fireball, one must have a object that is a ball and objectify it with fire and explosion properties, then throw it accurately
just as you'd do with a handgranade

How do we handle infatnicide? Common practice among wizards? Mostly banned? Do we get giant magical empires with baby sacrifices to the god-magus?

Babies are a source of raw magic. It's like drinking 98% rectified spirit or something. Highly toxic, hard to survive, highly mutates the user (highly mutated wizards are either scum of the earth childkillers that are hunted by special bounty hunters specializing in that business, or people who killed and consumed similarly "pure" creatures - like white unicorns, for instance).

I assume that a spruce of this baby pepper would make it a highly effective poison, which would bring the usual, shady, assassin types into an even greater moral valley, or perhaps different assassins would exist, ones with an anti-baby killing code of honor and those that don't give a fuck.

A disgusting practice only engaged in by the most morally corrupt Mages.
Banned by every nations with even the slighest regard for the rights of its individuals.

This has however not stopped many Mages from doing so in secret, and many an ancient war has been won by harvesting the youth of a captured population.

Tales are reguarly told of an ancient civilisation, where the firstborn child of every union was surrendered to the God-Magus in tribute to his great and terrible power, through which he maintained his dominance for 1,000 years, before being consumed by his son.

Banned, but it's difficult to enforce as some wizard parents will pretend their children choked to death or such in their sleep. As large numbers of religious systems in this world cremate bodies before burial, it's hard to prove that flesh or organs were taken from deceased children; due to their illegality, any wizards who create such Hearts will take great care to keep them hidden.

Typically, the final substance a Heart is objectified with is some of the wizard's own blood, hair or skin, providing the focus through which the wizard uses it. Modification of (and addition to) Hearts after this is possible, but risks destabilising or weakening them.

It is much less effective but also much safer to use little kids as catalysts. Girls for arcane magic, boys for divine.

...

Full dicepool based casting.

Declare the spell first and calculate a success threshold, including metamagics or any other assorted modifiers.

Player rolls their skill-based dice pool.
Meet success threshold = cast spell. Degrees of failure and success apply.

This is so high level mages can cast very effective low level spells and low level mages can attempt (but often catastrophically fail) high level spells.
I think this would be a fun basis for a mage focused system.