Marcel has been grounded for a month and over that time he would have spent in boredom, he’s been doing those mind dungeons he found in his treasure pile for quite a lot of time. Just by defeating monsters inside of their minds and getting stronger mentally, he also sometimes gets to take away a soul-related skill, like [Crushing Fear] and [Slither of the Poisonous Serpent]. [Crushing Fear] creates a mental trauma-related fear influenced by Marcel’s magic and [Poisonous Three-Colored Inferno Serpent] is a skill he got by being temporarily poisoned and possessed by a three-colored inferno snake inside the mind dungeon. This skill is only a semi-spiritual attack where he encroaches his enemy's surroundings in flames that are highly poisonous both physically and spiritually. How did that happen? Well, I’ll explain. 

[Flashback] 

When he picked up a certain mind dungeon a few days ago, he was met with more than he bargained for: An A-class dungeon semi-spiritual beast with a fully developed consciousness after been implanted into the illusory dungeon by the witches. It had stayed inside that place for so long that it controlled it like the back of its hand, which led to it being a particularly elusive opponent to fight again. 

The dungeon beast in question was of the Inferno Serpent species, a race of monsters living in B - A class fire-type dungeons and an incredibly rare find amongst its species as well with one Three-Colored Inferno Snake being produced amongst every ten thousand One-Colored Inferno Serpents and one amongst every thousand Two-Colored Inferno Serpents. It was a rare dungeon beast who specialized in utilizing three types of special fires with a soul so strong that its mere sight sent fears across those who met it, albeit its measly three-meter length and fifty-centimeter width and this one wielded strong soul-numbing poison as well? 

The serpent had a clear goal in mind from the moment it saw Marcel and planned its way towards that goal. This spirit-like serpent with immense soul power at its disposal worked tirelessly to keep Marcel on his toes that it seemed impossible to win at first, but then the serpent came close enough to him inside the fire-type mind dungeon to strike it with his sword and just when he thought he’d defeated the monster, the monster smiled ominously, sprayed him with a poisonous that left him unable to move his spiritual body and implanted every bit of its soul into Marcel and entered his body. Its goal all along was to take over Marcel’s body to regain life.  

Heading straight inside Marcel’s soul to take over his core, the little creature began laughing evilly as if it’d won the moment, it established a connection with Marcel’s soul but as it was about to learn, a mysterious force inside really doesn’t like intruders coming in and out of Marcel’s soul but hey, at least it was kind enough to not let it go back to its miserable life inside the illusory dungeon as a half-broken soul from the damage it had inflicted upon the little guy by kicking it entirely out of Marcel’s soul nucleus into the warzone that is the portion of Marcel's soul where the dragon and elven energies battled.  

Since the mysterious force allowed it to create a connection in the first place, it immediately took over it and robbed it of its memories and skills before kicking it out into the warzone where it was now stuck inside Marcel’s outer soul as a part of him as frustrating as it might be for the bodiless snake. 

[End of Flashback] 

The skill [Poisonous Three-Colored Inferno Serpent] is an amalgamation of the inferno snake’s abilities it’d gained during its life in the dungeon, excluding [Crushing Fear], of course. It being a semi-spiritual skill is primarily because it stayed true to the donor snake’s special composition. According to its memories inherited by Marcel, it was once a normal poisonous snake who ended up in an inferno of blazing hot hellfire. It somehow survived by using the hellfire flames to evolve, thus attaining its first color and characteristics from the red-hot blazing flame from the hell dimension it used to scorch its enemies to death. As it continued to survive in the dungeon and evolve to get even stronger, it eventually cast away its mortal body and threw itself into the fire again and this time, it gained two more colors, green and purple, something the other snakes had never figured out to do before. Each of the three flames it produced had varying effects. The purple flames are highly poisonous to both physical and spiritual lifeforms, the green flames damage the soul, and the red damages the body. 

After gaining two more colors, the monster naturally evolved until it was almost an A-class monster, but then it met the wrong witch and had itself trapped inside their invention. The snake wanted vengeance on those witches who sealed him away and so he hatched a plan to steal the body of the one that entered his mentally fortified realm. Marcel did and its plan worked, almost.  

Marcel woke up after the failed possession with the memories of the poisonous three-colored inferno fire snakes. He didn’t just wake up with the snake’s memories, he also had the snakes three different types of fires in the form of a skill and the mental strength it’d possessed. Now he could beat the Golden Lion he suffered so much humiliation against with a few attacks. It was like the world decided to help him fight against the souls of the creatures in the illusory dungeons. 

All monsters close to A-class develop a psyche and this psyche of theirs made it easier for them to deal with opponents. That’s the reason why they’re so hard to deal with. He was lucky that he didn’t meet that snake during its time in the dungeon or else he would have easily died at its hands. Marcel who reaped the benefits of the snake being stopped by the mysterious force inside his body couldn’t stop himself from dancing a victory dance. He also thanked the elven and dragon energies inside his body who were constantly fighting to attain dominance in his body.  

If not for the snake suddenly coming and getting in their way, leading to the energies joining together to slaughter the already-damaged thing to continue their fight for dominance on the outer edges of Marcel’s soul. Now the snake is not only half-dead but also a soul permanently stuck inside Marcel’s body, forced to integrate itself inside of him and makes sure that its power doesn’t turn to waste inside some human brat who did nothing to earn them.  

Speaking of powers, now that the snake thinks about it, Marcel’s body might not be the most terrible place to live. Because of the elves’ power rituals, Marcel has a lot of different natures currently floating around his body as the main consciousness of the natures fought with the dragon root’s consciousness in his soul and that makes it the perfect place for the little snake to live. He wouldn’t have to even bother worrying about going hungry with so many energies inside Marcel just floating around. Maybe with some hope, he might end up getting a physical shape again thanks to him. Whatever this mysterious force inside Marcel was, he didn’t know if it deserved his praises or curses. 

Marcel, after his victory dance, went to find Claude to ask to learn new skills that might help him in the dungeon. After all, Claude said at the beginning of his probation that if he manages to rest without using his magic, which he almost technically has, not counting the fact that mind dungeons do require a fair amount of magic to keep one’s spiritual body from falling apart while in there. 

Claude had said the past few days that he was going to teach this skill called ‘Thunder Rising’, a very cool-sounding skill that he created himself. Yes, Claude creates immensely dangerous but cool-sounding skills in his spare time but unfortunately, Marcel can’t use many of his skills were still not on par with Claude’s to be able to use them for long. If there was time after Claude was done teaching him this ‘Thunder Rising’ skill, then he might practice some of the magic inside the Sun Spell Tomb but since he isn’t an elf, it might not work, is what he thought. 

Marcel found Claude already waiting for him in their usual training place and there Claude began explaining the skill he created.