Having already died, Colas' soul entered a whirlpool at the center of which laid many worlds, among which Colas' previous modern and scientific world. Usually this whirlpool would wash any level of consciousness much less memories away long before the soul in question would revive. But in Colas' case, his 'cleansing' did not get to finish before he was pulled into a vessel. Of course this was by no means the universes' intention, but the result of black magic, necromancy to be specific.
The necromancer didn't know that a proper soul would be pulled into his minions, so he didn't care much for this dead servant he had enslaved, the shock of the 'cleansing' had also left Colas' soul a bit disoriented, so he acted just like a normal undead, following the orders of his master.
Until his master died; it could probably be counted as colas' negligence but cola didn't care as he was free.
But soon a problem came to mind, the main reason why his master died; a group of Witch-hunters had noticed his movements and seized his life in the name of the «holy lord» the group also set to exterminate Colas' life along with the other undead, but he managed to somehow trick them by playing dead, as for why he clung to life? It was of course to have fun.
Having been a servant of the necromancer he had picked up a little of black magic, but just enough to know that it was not the way to become the strongest in the world, but rather the way to become the ruler of a region. This was of course not his goal but the tools used by black magi would be useful to him on his quest, especially that one spell... it was dubbed 'Sacrifice' as the spell would consume lifespan aswell as soul energy to make you permanently stronger, as there was no previous incident where undead gained a soul with intelligence, noone considered the fact that sacrifice would no longer apply the lifespan cost of casting if one were undead. Essentialy creating an easy path to power for undead if they had intelligence. Infact before his master had died he had cast this spell on himself in a bid to defeat the witch-hunters, of course the witch-hunters had means to deal with it though, and so his master died.
There was also the issue of soul energy, it was something vague and usually would remain the same value even in death, the spells that used it were all spells that showed great potential if it were not for the gruesome consequences, and among them, as far as cola knew, only 'sacrifice' was suitable for him to use.
But spells weren't easy to perform, especially black magic, so he had to teach himself first, something that would require safety. So he began to wander, deeper and deeper into the forest, the forest was actually known as 'The Deep Forest' because of the way the trees got taller and grander the further in you got, it was said among humans that at the deepest, the forest would suffocate you, but despite such an environment there existed gargantuan monsters, as no matter what environment, there would almost always be something that could eke out a life there.
Having reached such a depth in the forest, Cola decided to call it a day and find shelter. Afterall habits die hard and he was previously a human, not to mention who knows how fast his body would deteriorate if he didn't take care of it, he had already experienced death by such a wierd means so he would of course not underestimate natures' ability to decay and decompose.
Having thought about it, he found a thick tree in the vicinity and started digging a hole for himself underneath it.
It was nothing special, really, just a shelter from nature, having the roof consist of dirt and roots while his walls and floor consisted of stones he couldnt dig up and compressed dirt that he struggled to dig any further. As for how he dug? With no tools at the ready he dug using his hands, and depositing the dirt in the general vicinity while spread to hide the exact location of the hole.
Having found shelter Cola resolved to use the spell on himself, drawing up a magic circle in the dirt to amplify the effects of magic, he sat down and recited the spell made using an ancient language.
«... mér styrk...»
Being the first time he performed the spell, he of course didn't succeed, but he could feel that he had uttered the spell wrong somehow. Or maybe it is impossible to use the spell with his undead body? Either way he tried again, slightly altering the process in an attempt to understand what went wrong.
After about 50 tries and removing different phrases from the spell he finally found one that worked, he could feel... his bones hardening? Was this a cruel joke played by the gods of this world? Nevertheless, good defence is a kind of strength so he continued using the spell until an unexplicable tiredness washed over hos body...
Once he woke up he could feel that he had come close to completely scattering his soul by casting that spell too many times, nevertheless he cast the spell about 8 times and when he was observing the bones in his arm he could see the light glint off of it in a peculiar manner... almost as if his bones consisted of gemstones...
Thinking back to the sciences of his previous world he seemed to remember that most creatures are carbonbased creatures, that was to say most creatures had cells built around carbon, thinking about it some more he made the connection. Under high pressure carbon would turn into diamond, it's not that it was no longer carbon, but the structure was tighter and sturdier, by a lot.
Looking at his bones that were almost seethrough with a predominantly red-blackish coloring, he came to the conclusion that the carbon in his cells had turned to diamond.
He had no proof though and as such he just deemed it as one of his theories. He also noticed that his build had reduced by a lot, his body which was originally that of a zombies' was now a skeleton, and he had become a whole lot shorter, infact he was only about 1 meter tall. One of the functions of undead was to assimilate lifeforce from life though, so once he ran out of flesh he used the energy coming from the roots of the tree above himself.
After a few more tries with the spell he felt that it could no longer improve his body, but just as he was contemplating what to do he heard a creaking sound, it became louder and louder until the sound that reminisced a twig breaking became the sound of a tree hitting the ground.
Turns out taking the vitality of your very heavy but kind of unsteady and shaky roof is a bad idea, as he was submerged in the dirt and rubble and stone by the trees' roots he realized he would have to try and get out now, but as a victim of circumstance he wasn't any stronger physically, only very robust. So he could only try to slowly dig his surroundings and compress the dirt below him in order to bloom out of the earth like a flower. Once he exited the earth several months later he finally noticed something peculiar, it felt like his size had reduced even further, peering at his body it was no longer than his previous forearm was, and his bones were completely seethrough except some bloodvessels and nerves aswell as his bonemarrow.
And just like that, the Undead Pygmy Skeleton Cola started his path to becoming the strongest.
Except he couldn't enter any society like this, and so how would he know how to get stronger? So, he picked up a relatively thick stick for his size and sat to work on sharpening it into a miniature and crude spear.
Having remembered from the modern world that spears were the simplest weapon to pick up among the cold weapons.
He tried brandishing the spear in what could only be considered as the spear version of shadowboxing, but found his fine mechanics to be shaky at best, he was a skeleton afterall, and a weak one at that.
Having practiced for a few days he decided to try his luck by hunting wildlife from the vicinity.