(These are my headcannons that will be incorporated into my books.)

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Soulings(unborn skeletons) appear as a small ball of light in their Carriers(birth parents) Soul. They usually appear in litters(multiple at once). Two to three being the most common and ten to twenty being rarer.

The ribs protect the Soulings through this time along with the Carriers magic forming a bubble like membrane around them. Depending on how many Souling a Carrier has determines how long they will stay Soulings. From 5 moths to a few years.

During birth the Soulings will faze through the magic bubble, causing the Carrier discomfort and pain. The Soulings will float down to the hip as the bubble membrane dusts. The dusts will flow around the Souling and form their body. This can take for thirty minutes to an entire day depending on how many Soulings and if the Carrier had given birth before.

Newborn skeletons are very small, as small as a newborn kitten, and are called Skullies.

Skullies, after birth, are completely dependent on their Carrier. They have to feed off their Carriers Soul for the first year of their lives.

Skullies have a very strong grip used to hold onto their Carriers inner ribs. This is to be close to the soul at all times to feed and for protection. Weaker Skullies usually have a weaker grip and will have to be held by their Carrier at all times so they are not injured falling.

When the Skullies turn five months old they are to large, being the size of a one year old, to be carried in the ribs. At this time they are large enough to walk and not have constant feedings.

For feedings the Carrier needs to lay or sit for the Skullies to get close to their rib cage.

Skeletons grow at a slow pace when it comes to maturity.

Form the age or 1 to 20 Skeletons are called Skullies. They grow at more half rate as a human child.

After 10 they are the size of a toddler and can eat normal food to gain energy but are still need their Carriers magic.

Near the age of 20 they are the size of a 10 year old. The Skullies souls will disconnect form their Carriers Soul and no longer need to feed from them. Skeletons at this stage are called Skeles.

Skeles grow at a very slow pace. Nearing 100 before they become Skeletons.

Skeletons go through their 'teen years' during this stage.

When a Skele reaches 100 they stop growing and are fully mature, about the same as a human 20 year old. At this time they are now Skeletons and can carry or sire offspring.

They still will feel a connection with their Carrier and depending on their relationship will visit their parents every so often.

Skeletons that live until 10,000 are labeled as Greater Skeletons.

Skeletons that live until 1,000,000 are labeled as Eldritch Skeletons.