Natural Ascension.
Ascension is a step of rising above one's mortal nature by improving the quality of one's essence and body. This can be slow or fast, depending on how one refines themselves naturally or by absorbing the essence or by killing stronger beings and absorbing their escense (Sunny can't do this effectively). Once the soul esence reaches a qualitative change, the soul core, well shadow core in his case, will re make itself and grow stronger. Co refinement is necessary for this process. (Wiki for the win, chapter 1306 in shadow slave)
Sunny was using both methods, hunting creatures at the perfect times at night when his aspect shined (or well, dimmed) and at noon when his aspect was at its weakest to learn to fight. He mastered the third step of his aspect legacy and got a divine memory called [Shadow Lantern].
It allowed him to call shadows inside of it, and instead of giving light it absorbed light.
His soul arsenal was pretty good, mainly with memories he made himself, although he was warned to not rely on it much, especially after transcendance since Will is quite important to weild, especially for supremacy! Even gods themselves didn't use tools, instead they created concepts to fight some creatures? He had no idea since that bast- Alex didn't tell him much though he sincerely doubted if even Alex knew the information
Apart from that, during their time spent together he grew fond, though he would admit this to himself, of that guy, Alex, who still had many secrets but he didn't mind it! He desperately tried to connect his reasons with logic— the logic that if Sunny was betrayed Alex would fail— and well partially succeeded even if he trusted him more than just logic would allow. Even the girl who greeted him in the start ascended the same time he Awakened.
He started the process of ascension 5 months after he Awakened and followed the cycle of learning to fight in any conditions given, and Sunny tried to take as many advantages as possible! He formed the devil core around 3 more months after that.
He checked Nephis' runes once a day to set a mark, she was already tyrant close to being a terror:
Soul fragments: [3999/5000]
And seeing her memories he could tell she was in a Nightmare, he couldn't tell earlier due to different memory descriptions but only figured it out a while later realising, one consistency, she was battling both captors and slaves in a colloseum...
Sunny sighed 'I bet she's with them right now, thei- her cohort' He often tried not to feel jealous but failed every time, it was always lonesome. He recalled every laugh they shared, every jokes and many things but that was always followed by pain and longing. 'They won't miss you anyways stop feeling this way'
This was the main reason that the first thing in the morning he did was use soul serpent's [Soul Weapon] form to make an odachi and practice with it until he started learning different weapons like a scythe.
Five more months later Sunny ascended, he successfully reformed his Shadow Core and refined his escense. The sadows danced around him as they witnessed the birth of their new master.
[Your attribute has evolved.]
[Your attribute has evolved.]
***
Atop of Noctis' ship Nephis, in the body of creature made of light not exactly possible to describe with words, was discussing the final confirmation of their plans, they retrieved the last knife needed and were discussing how to proceed with Noctis.
Nephis witnessed Sunny's runes change and felt a smile forcing its way on her face.
"What's wrong princess?" Effie asked, amused, "we are in middle of discussing a battle are you that thrilled with it?"
"Sunny!" Was all Nephis managed to say. Well 'say' for her was wrong because it was some weird artifact that read her thoughts out loud, she couldn't exactly speak with the creature she was inhabiting's body
Hearing that Kai fell off his chair and Effie, for once dropped the food in her hands! And choked on it... As for Cassie she had the faintest hint of a smile.
"Did doofus ascend!?" Effie screamed, forgetting her food for a second "and that too before us?" And proceeded to grab another bite...
Kai, too, had his eyes widened in shock, which was only visible to Nephis after he got up... He was speechless
"Do you think he ascended naturally?" Nephis asked with a sad tone, she really wanted to meet him now and apologise properly and gift him an echo she got.
None of them replied, uncertain how to answer her question.
"Do you think he will like my gift... Its a Shadow creature after all and they would probably feel kinship?"
For that question she got a nod.
***
Now that Sunny ascended he could do more complex Weaves and well maybe even make transcendent memories, albeit for now it would take a few days due to lack of perfect escese control, granted it was probably better than most ascended in the waking world already despite just ascending.
He sighed knowing what was to come, he was going to make an ascended memory of sixth tier since he was using six soul shards to be safe, unsure of the exact amount needed to sustain the weave.
This memory would allow him to store living things inside it and further modified by him to allow them to breathe and sustain life. This one took him a whole month to learn along with some other memories, on the bright side it was before he ascended!
Sunny began weaving, and it lasted a few hours, and by the end of it noticed his body full of sweat and empty cores. He collapsed on the ground.
[You have recieved a memory!]
He heard the spell.
He did it.
The most complex weave he could make as an ascended devil.
It could roughly carry 20 people.
"You are getting quite close to your goal" Alex said "and the Nightmare's, we'll have to end it in about six months you know?"