(Tiny bit of semi-lemon, but nothing explicit. Probably as close to NSFW as I'll get)

The human king leaned over the tub and slowly waded his hand into the lava bath, grimacing at the gooey feeling as it went through his fingers. He was naked except, of course, for the amulet that still dangled from his neck.

"Are you coming in or what?" the Queen asked, already chest-deep in the stuff.

"Yeah, yeah I'm… I'm working on it…" Finn responded timidly.

Slowly but surely, he brought both of his legs over the edge and into the lava-filled bathtub, opposite to his wife. After some delay, he began hesitantly lowering himself until he was eventually sitting in it like the bare Queen in front of him. He shivered at the sensation of his lower body being submerged in the goopy magma.

"Guh… I don't think I'll ever get used to this stuff…" he said weakly.

Flame Queen smiled and raised an eyebrow at him. "It's been 10 years, hon. Quit being such a baby." she joked.

"I'm not! It's just… this stuff feels so weird. I guess I'm more of a 'water' man." he said, splashing a bit of lava around. "As long as it's not the ocean."

"Well I, for one, think it's very relaxing." she said as she sat back and stretched her arms. "Pretty much all fire elementals do. I guess I just thought you'd start enjoying it too by now."

"Yeah, well, maybe I should take you for a dip in some water sometime, see how you like it!" he teased, poking her leg with his foot.

"Ha, no. I don't think so."

Despite Finn's teasing, Flame Queen could tell he was still really uncomfortable. She supposed it was unfair of her to assume that a human would be totally used to something like this, even after living in the Fire Kingdom for so long.

The Queen gave him a sly grin. "Hey, I know something that'll make you feel better…" she said as she leaned forward and over him. She brought her hand to his bearded face.

"Oh yeah?"

"Something that will take your mind off the lava…" she whispered, sliding her hand down to his chest.

"Oh…" he smiled, bringing his hands to her hips.

She slid her hand down his stomach, into the lava, then down to his waist. Lower and lower until—

"MOM! DAD!"

The bathroom door suddenly swung open and in ran two boys, no more than 8 years old. The older of them, a humanoid fire elemental with flaming blue hair, ran in first calling for his parents. The younger one, a small human boy with short red hair, was close behind chasing after him.

Startled by the sudden intrusion, Flame Queen quickly went back to her side of the tub, covering her chest with her arm. Finn attempted to quickly recompose himself.

"Pyre, what did I tell you about knocking?!" the Queen said sternly, the flames of her hair crackling with frustration.

"But Fenix is doing it again!" the young elemental whined. He then looked at his parents curiously. "What were you two doing?" he asked.

"We were, uh…" Flame Queen gave her husband a worried look.

"Hugging?" Finn finished the sentence for her.

"Yes… hugging. We were hugging." she answered. Thrown off by the question, she quickly regained composure. "Anyway, what's the problem this time?"

"Fenix keeps stealing my toys and stuff!" Pyre cried.

"I was not!" the little human next to him insisted.

She directed her attention towards Fenix, giving him a stern look. "Fenix, you know how I feel lying."

"But I—" He was about to continue, but his mother silently continued her rigid look. "…Okay... Sorry for stealing your stuff, Pyre…" he said in a defeated tone.

Pyre simply crossed his arms and pouted, but the King and Queen were satisfied with his apology for now.

"Thank you, Fenix. Now both of you go finish your homework. Dinner should be ready in an hour; we'll have a talk about all this after that." Flame Queen said.

The boys walked out of the bathroom, still bickering with each other. Relieved, Flame Queen slumped back down into a reclining position.

"I swear, those two have been at each other's throats lately." she sighed. "I just wish they could be as close as you and Jake…"

"Yeah, I hear ya." Finn replied. "Honestly, I think the problem is with Fenix. He keeps acting up and I don't know why."

"I agree. You and him seem to bond really well, so I think you and him should have a talk. You know, human-to-human?"

"Yeah, I think you're right. I just hope I don't screw it up. I worry about the little guy…" Finn sighed, resting his chin on his hand.

"Don't worry, I know you'll do fine." she assured, giving him a warm smile. "Now then…" she leaned over to him again. "Where were we?"

After dinner, the Queen took Pyre into another room to talk with him separately, leaving Finn to talk to Fenix in the living room. What she said was true; Finn and Felix shared a special bond, being the last humans in existence. Not to mention, being a human in the Fire Kingdom wasn't easy, even if Fenix was born there. Finn was ecstatic when he learned that his son would be pure human, as it meant he could save humanity from disappearing completely.

The boy shyly sat on the regal-looking couch, twiddling his thumbs. His father sat down next to him, placing a hand on his shoulder.

"Hey, champ. You wanna tell me what's wrong?" Finn asked gently.

"Nothing…" Fenix said meekly, looking down at his hands.

Finn chuckled a little at the response. "Come on, kiddo. I know your old man isn't that bright, but I know when my son's got something on his mind. Now come on, tell me why you keep bothering your brother."

The boy remained silent for a moment, then finally spoke up. "Okay… it's because… it's because I'm jealous of him…"

"Jealous? Why?"

"Cause I don't wanna be human! I wanna be a fire elemental like him and mom!"

Finn's heart sunk when he heard those words. "What? Why wouldn't you want to be human?"

"I can't shoot fire or stuff like everyone in school! Plus I have to wear this amulet all the time. Humans can't do anything cool…" Fenix said.

"Oh no no no, don't say that! Humans are awesome! Just… in our own way."

"Really? Do we have any powers?" the child asked expectantly.

"Well, uh… not really…" Finn paused, trying to think of something to say. He hated to admit it, but Fenix had a point. Compared to all the magical creatures of Ooo, humans weren't particularly remarkable.

"Okay, so we don't have any powers." Finn continued. "But you know what? That never stopped me! All I needed to kick butt was a sword and my brother! And look where I am now! Besides, being human makes you special. Really special!"

"It does?" Fenix asked with hope in his eyes.

"You bet! You've got an important duty as a human! And that is to make tons of babies!" He blurted out.

"Ew! Dad!" Fenix laughed, playfully punching his father.

"Haha, okay okay!" Finn chuckled, defending himself from his tiny blows. "But y'know, you're not giving humans enough credit! You know what? I think…" Finn pondered, scratching his beard. "I think it's time I give you something."

Finn got up and went to the display wall, where sat his many trophies, treasures, and souvenirs from his adventures throughout the years. One of the items on display was an embellished silver sword, somewhat smaller than some of the others on display. He took it off the mantle and presented it to his son.

"I was gonna wait a few more years for this, but I think now's a good time. I want you to have this." Finn said, placing the sword in Fenix's hands.

The boy's eyes sparkled with bewilderment. "Wow, really?!"

"Yup!" Finn smiled. "This is the sword I used when I was your age. I eventually grew too big to use it, but it should be the perfect size for you! I wish I still had the sword my dad gave to me, but this'll have to do. Just promise me you'll be extra careful with it, okay?"

"Yeah, definitely!" Fenix responded, his eyes still fixated on the sword.

"What do you say next week me and Uncle Jake take you and your brother out for your first adventure?"

"YES!" Fenix answered immediately, putting down the sword and wrapping his arms around his father. "You're the best, dad!"

Finn hugged him back and gently patted his head. "Hehe. I have a feeling this'll help you two get along better." He said, rustling the boy's crimson hair. "Who knows? Maybe you'll end up just like me and Jake were! A human boy and his magic bro out on adventures! Just like old times…"