Strange Creature

Only wavy sounds of the waters and movements of the sea creature sounded within Finn's ear.

He sat on the top of the dome-shaped barrier with peak concentration as he cultivated his core.

His first aim to fully replenish his core was accomplished, the mana density making it easy for him to pull the mana into his core.

He was now slowly but successfully increasing his core size.

Finn didn't need to eat or sleep since he was in his Ghost form. He still took breaks because there was still a mental toll from doing nothing but concentrating. 

These breaks occurred when he felt the day hit midnight, spending it exploring the surroundings.

Aside from confirming the fact that these weak sea-creatures didn't live long, he noticed the range this barrier was covering was abnormally big, yet it looked small. It was very complex that he gave up on it.

After spending 17 days cultivating his core, it was midnight, time for his break. Currently, his core was the same size as the Fenrir's.

Finn sighed, satisfied with his progress. 

Suddenly, he was on alert as he sensed a presence not far from him. 

Said presence was slowly approaching him.

It was one of the strongest he had felt since he had gotten here.

In his spirit body, Finn stood on guard, prepared to engage in battle.

As the presence drew closer, he could barely identify what it was. He could vaguely see its silhouette, the creature seemed to blend with the water.

Finn came to realize that not all creatures were hostile, so he refrained from attacking since he didn't sense animosity.

Soon, the creature came to view, giving Finn a confused, yet interested, reaction.

"What is this? A jellyfish?" He questioned aloud.

The creature had a body shaped like an umbrella with multiple wiggling long tentacles. It was slightly luminescent and its ocean colored body was almost clear.

With the creature now staying about a meter from him, Finn felt the unconcealed mana core of this beast, impressing him. 

Ever since he left the Fenrir's body, he encountered creatures; there were those who moved on instinct, those who had a mild level of intelligence and those who had impressive intelligence.

Finn could tell this Jellyfish creature was moving on instincts.

The Jellyfish looked at Ghost Finn, before circling him and playing.

While Finn contemplated possessing this non-aggressive creature, it just kept playing around him.

On the one hand, he didn't want to steal the body of a creature that was not only free, but it was also 'playing' around him. On the other hand, this was an opportunity, this creature's core size was large, unbefitting for a creature with its intelligence.

This opportunity to possess a non-rational creature, which he can easily possess with his gained experience, might never come again. 

All this pondering even made him start contemplating if he could actually defeat that Bat creature that seemed to be connected to the rest of its flock.

At the end, Finn decided not to. It went against his moral of interfering with the freedom of beings that doesn't deserve to be interfered with. If he was a monster of sorts now, he still needed his human morals to avoid him from losing himself to monstrosity. 

Just then, when Finn was about to continue his cultivation that was nearing its end, he saw the Jellyfish that had been moving around position itself in front of him.

The Jellyfish rose one of its tentacles up, pointed at Finn, then itself.

Finn was bamboozled. 

"What?" he blurted out.

The Jellyfish just 'stared' at Finn seeing he failed to understand it. It raised its tentacles up again, moved it like a swimming human, and dipped its tentacles into its body's bell.

'It's saying I should enter… no, possess its body? It has intelligence! How does it know I need to possess a body?' Finn questioned, seeking an answer. Now that this creature had intelligence, he couldn't trust it anyhow!

Seconds passed by with either party making any efforts to communicate again.

In this short period, Finn could only think of this.

'It knows my nature and wants me to possess it… There's also the fact that through intentions can be unknowingly let out through the spirit body, like how I communicated with the Fenrir. Did I release similar intentions when I was considering earlier and this creature sensed them?'

Before he could further think, Finn felt the Jellyfish go through his spirit body, making him yell at it, "Hey! That weakens me y'know!"

But the creature didn't stop, repeating similar actions.

With hints of hesitation still lingering, Finn said, "Fine, fine. I'll be possessing you now…"

In response, the jellyfish 'jumped' around, glad that Finn made such a decision.

Finn moved towards the Jellyfish, ready to possess it.

As he entered it, he said, "Thanks. This will save me a lot of stress."

…

Finn found himself in a dark sea, similar to the luminescent sea floor of the mana source's surroundings.

Feeling that he only needed to possess the body now, he expanded his spirit body, until he sensed the jellyfish's presence.

Like him, the Jellyfish was now of towering height of nothing less than 10 meters. It's appearance was still similar to that of its material body, the only difference was that this beings spirit body seems to be a merge of multiple spirit bodies.

It looked like multiple fabrics that were sewed together.

Additionally, the playful and kind demeanor of the creature had gone, replaced with the thirst to conquer its foe.

In his huge darkish-blue ghost form, with a body like a curtain that had limbs, Finn smiled as he saw the creature approach.

With an ethereal voice, he said to the creature opposite him, "Of course it's like this. No being will willingly give up its life for an unbefitting reason."

Finn turned his fingers to claws ready to fight.

In this battle, he would give it his all and win this fight.

As the long tentacles of Jellyfish extended, eager to entangle Finn's spirit body, Finn grabbed the tentacles with his huge hands. 

He spread his arms, leaving the 'face' of the Jellyfish open. 

Feeling disgust and mockery due to its actions, Finn let out a loud, spirit shaking cry.