A/N: Hi there! Muses have been working overtime for me, apparently. This little bundle of joy came out of nowhere, but I'm very happy with it. It's going to be roughly between 7-10 parts, depending on how much I ultimately end up writing. As of now, part 6 has been started but is not close to completion. I'll be posting daily on this one since it's so close to being done (I think).

A Lifetime of Love

~*~PART ONE~*~

Grillby chuckled to himself as he watched Sans and Papyrus play on the plastic equipment. Sans, a mere six years old, was already in second grade and passing third grade math tests. He was reading at a fourth-grade level. His social skills were through the roof; he could charm his way into getting almost anything he wanted. He excelled in nearly every way.

He sure as hell was Gaster's son.

Papyrus, on the other hand, was barely three years old. He'd just started running everywhere and rarely knew how to stop talking. He adored puzzles and had even created some of his own already. He had more energy than a lightning bolt, but he wore out quickly. Even at three, he had more compassion than most adults Grillby knew. He'd give up food if he thought his brother was hungry.

Not that either of his children ever went hungry, but there had been an occasion or two where Sans tricked his younger brother into giving up his afternoon snack.

Papyrus was certainly Grillby's son.

The fire monster smiled to himself when Sans sneezed. A whiff of blue fire burst out from in between his bones and dissipated in smoke. It was adorable.

"Bless you," Grillby said.

"Thanks, Dad," the kid replied. He came up to the fire monster and held out his hands. "May I have some cleaner please?"

Such a gentleman, Grillby thought. He dug in Papyrus' baby bag and brought out the bottle of hand sanitizer. After a quick squeeze into his son's hand, he watched as Sans carefully spread it around his phalanges and metacarpals. The boy was always careful.

"You could say I've sanitized the situation," he said with a grin.

Grillby grinned back. Humor was something his son had inherited from him. Funnily enough, Papyrus seemed to have gotten his other father's no-nonsense approach to life.

"Very clever, Sans."

Sans smiled proudly and went back to playing.

The park was nearly empty. It was usually more crowded than this with many monster children playing around to keep his children company while he read. Today, it was Sans and Papyrus and another monster who seemed more interested in digging in the sand by themself in the corner. Even after Sans attempted to approach, the other monster wanted nothing to do with him. It was odd, but not altogether unheard of.

So instead of reading, Grillby kept an eye on his kids to make sure that Papyrus' energy wasn't hindering Sans' creativity. They seemed to be getting along famously, which was a nice turn of events. As compassionate as Papyrus was, he wanted things to go a certain way when playing. If the boys' ideas of the game didn't mesh, there would be screaming involved quickly.

For now, Papyrus was captain of the ancient Royal Guard and Sans was the enemy. They both played with magic, their eyes lit with fire—Papyrus with orange and Sans with blue—as they decided which attack to throw at the other. Their attacks were soft, causing no damage as they hit the other.

Grillby looked up when someone else began approaching. He was a little unnerved to find a human couple walking up with their child. They looked apprehensive, but the child was all smiles. There was some hope, he supposed.

Humans were not known for letting their children play with monsters. Humans were more known for shoving monster children down and calling them names, even when they themselves were adults.

The elemental's flames brightened just a little out of a need to protect his children.

The child—a girl that looked around Sans' age—started running toward the playground. The human parents did nothing to stop her. She stopped at the edge and looked at Grillby with a wide grin for a second.

"Can I play?" She asked with wonder in her voice.

Grillby crackled a little. "If you wish."

Her eyes widened as she looked at him. "You sound cool. You crackle and stuff."

Grillby couldn't help but laugh. "Yeah, I do."

"Frisk," the woman, he supposed she was the mother, chided, "don't bother the monster."

The girl scowled and looked back. "I wasn't bothering. I wanted to play."

Both the man and the woman gave Grillby and his sons a concerned frown. "Maybe this isn't the best day to play."

Without a word, the girl walked up to Sans, mid attack, and thrust her hand in his face. The bones he'd been throwing at his brother merely bounced off of her skin. She laughed.

"That tickled. I'm Frisk."

Sans looked up at her, a little miffed that she'd interrupted his game. "I was about to win."

She quirked her lips. "I'm sorry. Can I play?"

"Sure. You can be the human, and my bro and I will be the Royal Guard."

She wasn't really sure what that meant, but she liked the idea. "Okay, what do I do?"

Papyrus frowned. "NO!" he yelled.

Sans gave him a look. "Come on, Bro. It gives us authenticity."

Papyrus squirmed to stand up and ran over to his brother. "Play with you." He held his hands up.

"You are playin' with me, Paps. We can add another player, right?"

Papyrus shook his head. "NO!"

Sans groaned. "Daaaaaad!"

Grillby snickered to himself. "Papyrus, let the girl play."

He huffed and sat down hard by Sans. He crossed his arms with another huff. "She's human," he grumbled.

"Yes, she's human, but that will just give you more options to play. Please don't play Royal Guard with her. She's not an enemy."

Frisk turned to look at the fire monster with a dark look in her eyes. "But I can be," she all but growled. She turned back to the boys and pretended to capture Papyrus. "I got him!"

Grillby was impressed. Humans were usually put off by any reminder that they'd done anything wrong in the past. He could tell that her parents were exhibiting that exact behavior now. They were shifting in their seats on the bench five feet from Grillby's and whispering to each other.

"No, not my bro!" Sans called out, clearly acting. "Unhand him, you fiend!" His eyes burst into blue flame as he conjured bones to throw at Frisk. Like with his brother, the attack was soft and caused no damage.

Frisk pretended that it did. "Ow!" she yelled and toppled over.

"Frisk!" Her father cried out.

Frisk laughed. "I'm fine, Dad!" She lifted her head and gave a thumb's up before laying back down and pretending to have been badly wounded. "I'm not sure I can make it through. You guys need to help me."

Sans lifted a brow bone. "Why would we do that? You kidnapped my brother." He held Papyrus protectively as the little monster squirmed to get away.

"Because I was trying to save him from another band of humans, a bad band." She lifted her head again to look at the monsters. "It's not my fault you didn't listen to me when I said that the bad band was on their way."

"Oh." Sans put Papyrus down and went to 'save' Frisk. He used pretend healing magic. "I learned this from my dad." His eyes glowed purple as he gave a soft healing pulse.

Frisk sat up, all healed. "Is that your dad?" She pointed to Grillby.

"Yep, that's Grillby. I get my fire from him. The other stuff, like my bones, I got from my other dad."

She was utterly confused. "What about your mom?"

"I don't have a mom." Sans was confused as to why Frisk was confused. "I have two dads."

She considered that for a minute then decided to just go with it. It was pretty obvious it worked somehow or another. "My parents are over there. AnnaLee and Jordan." She waved at her mom and dad. They waved back. They had settled down a little after watching their daughter play.

Grillby watched the kids play for a little longer before he decided he'd better introduce himself to her parents. He liked to get to know the parents as much as his children liked to play with their kids. He looked over at the parents and noted that they still looked a little edgy. Perhaps getting to know him would put them more at ease.

He stood up and walked over to their bench.

"Hi, I'm Grillby," he said, without extending his hand. Most humans didn't want to touch a walking fire.

AnnaLee stood up first and smiled. "Hi. I'm AnnaLee, and this is my husband Jordan." She grabbed his shirt and tugged to get Jordan to stand up. He did and smiled at the elemental.

"Our kids seem to get along quite well." Grillby glanced back at the kids and laughed when Frisk pretended to have magic and attack an invisible enemy. Sans corrected her form.

"Frisk has always been friendly with monsters," AnnaLee said. "My mother is a bunny monster."

"Adopted mother," Jordan whispered loudly.

AnnaLee rolled her eyes. "Don't." She smiled a little too dramatically at Grillby. "Where's their mother?" She asked.

Grillby tried not to show his concern. Not only was he a monster, but he was a male monster with a husband. That didn't go over well with most humans, either. He cleared his throat.

"My, uh…my husband is at work."

"How does that work?" AnnaLee asked. Jordan elbowed her in the side. She glared at him. "I was just asking."

"Well, he works most evenings, and I work during the day. We have our weekends together, though." It was a bit tough, but it paid the bills.

AnnaLee quirked her lips. "I actually meant…I mean, I'm assuming that you guys made the baby skeletons together."

"Oh." Grillby wasn't sure for a moment why she questioned it before he realized that they probably didn't know. "We make babies with magic," he said with a bit of a blush. He knew all about how humans made babies, and it was weird. Weird, and strangely taboo. He wondered if humans considered the monsters' way of making babies also weird and taboo. If so, he probably just crossed a line. Then again, she'd asked.

"Oh, that's right," AnnaLee chuckled. "I can't believe I forgot that. I always thought that was so cool. I'm sorry if I'm making you uncomfortable."

Grillby just smirked. "Nah. There's nothing offensive about how we make our children," he answered. "Sometimes, humans want to make it that way. I can understand, with how you…yeah. But with us, it's a lot different than…well…" He decided to stop there. He really didn't need to discuss his love life with strangers.

Instead of continuing the embarrassing conversation, he turned around to look at the kids. He barked out a laugh when he realized that Papyrus and Frisk were burying Sans in the sand. Not just burying…they were building something on top of him.

"DAD!" he screamed.

"What?"

"I'M A SANSCASTLE!"

He couldn't help but snort. "That's sans-sational!"

Sans beamed and giggled as the other two laughed along with him.

"That is adorable," AnnaLee said with a sweet smile.

Jordan even seemed to be warming up to the idea of his daughter playing with monsters. As they talked, Grillby uncovered the man's hesitation. It wasn't the fact that they were monsters; it was the fact that they had been using weapons magic near his daughter. He didn't want anyone to get hurt, least of all his own kid.

Inevitably, Sans wanted to get out of the sand. Papyrus wasn't done building. When Sans moved and caused his precious castle to crumble, Papyrus sat back and screamed.

Grillby rushed over to them, afraid someone had been hurt.

"I just wanted to get up!" Sans all but shouted.

Grillby picked up his youngest son and nodded. "It's okay, Sans. Paps is probably just getting tired."

"I'm not tired!" Papyrus grunted through tears. As he rubbed tears away, he couldn't help but rub a little harder than normal.

Grillby smiled at the sweet action. "I think you are."

"I'M NOT TIRED!" The little monster squirmed, but it didn't have his usual push. "I WANT TO PLAY!"

"What about hungry?"

Papyrus considered that for a moment. "Yeah."

"Me too!" Sans piped up. "I'm hungry."

"Me three!" Frisk whined.

AnnaLee laughed. "You ate before we came here."

She shrugged. "I'm hungry again."

"Dad! Can Frisk come over for dinner? Please, please, please, please, please?" He folded his fingers together in a begging gesture. "I promise I won't bug Paps for the rest of the night."

He looked at Frisk's parents. "I'm not the one you need to win over, Kiddo."

Sans looked at Frisk's mom and dad and swallowed hard. He glanced at Frisk. "You ask," he mumbled to her.

"You have to come with me." Frisk reached out and grabbed the still-sandy sleeve of his shirt.

That, he could deal with.

"Mom? Dad?" Frisk began.

AnnaLee smiled. "Yes, Frisk?" They were going to make her ask; this was too cute.

"Can I go over to their house for dinner?"

"Please, can she come? My dad's the best cook! I promise, we'll take care of her. I won't even use magic anymore."

AnnaLee and Jordan looked at each other. AnnaLee was all for it. It wasn't a school night. They didn't have anything planned. If anything, letting their daughter go to dinner with her new friends was a way they could get some alone time. At the same time, they had only just met one of their fathers.

"I'm assuming your husband will be home tonight?" Jordan asked.

Grillby nodded. "He usually gets home around eleven on Friday nights. Our children are allowed to stay up to see him because it's not a school night. Of course, Frisk wouldn't have to stay that long."

Frisk was granted permission to go. While the kids celebrated with hoots and high fives, the grown-ups exchanged phone numbers. Grillby gave AnnaLee and Jordan directions to his home. It was decided that they would drop her off so they could see exactly where he lived.

"Shake off, Sans," Grillby called out. "I don't want all that sand in the car."

Sans shook, his bones rattling as he did, and sand fell to the ground.

"That's a funny sound," Frisk said. "It's like a xylophone."

"I don't sound like that!" Sans retorted. "It's just my bones."

"My bones don't do that." She tried it. No rattling.

"That's cuz you're all fleshy." He reached out and pinched her arm lightly. "You squish instead of rattle. I can't squish." He tried it. "See?"

They were all soon on their way to Grillby's house.

"Can I have some more?" Frisk asked, holding up her plate.

"Of course," Grillby and Sans answered at the same time.

Grillby smiled at his son and took the girl's plate to pile more spaghetti on it. When he put the plate back in front of her, she began inhaling the pasta again.

"Sketti!" Papyrus yelled. "Sketti!"

"Do you want more, too, Paps?" Grillby asked.

Papyrus nodded. "Can I have some more sketti?"

Grillby put a little more on his youngest son's plate. "You got it, Kiddo."

"Can I sketti outta here?" Sans asked. His plate was clean. "I'm full."

"You should wait for your guest to be done," Grillby said. "It's only fair."

Sans looked at Frisk. "Are you done yet."

"Sans!" Grillby laughed.

Frisk shook her head. "Nope," she mumbled through a mouthful of noodles.

Sans sighed and waited for Frisk to finish her plate. While he was waiting, he decided to take a few noodles to draw with. Grillby didn't mind, as long as the kid was behaving himself and not making too big a mess.

As soon as Frisk was done, Sans all but dragged her to his room. He was too excited to show her some of his toys. Together, they played with Legos and talked about what they were going to be when they grew up.

Sans was going to be a scientist like his dad.

"You mean your dad downstairs?"

Sans shook his head as he connected two pieces together. "No, my other dad. He's working right now, being a real-life doctor scientist. He's so cool."

Frisk nodded and dug through the bin of Legos to find a piece she needed. "I'm gonna be a doctor, too," she said. "I'm gonna help people when they're sick."

"Dad's not that kind of doctor. He does really cool space stuff. That's what I'm gonna do, too."

"So like an astronaut?" She asked.

"No, but he helps the astronauts get home. He makes really big decisions and sometimes he saves lives." He put the last few pieces on his rocket and started to fly it around the room with magic.

Frisk laughed. "That's so awesome!" she cried. "Even though you said you wouldn't use magic."

"I meant weapons," he countered. "This isn't weapons. I can fly yours, too."

She nodded and held up her little dog. It was soon surrounded by blue fire and flew up to sit on top of the rocket. They both laughed together as they thought up strange scenarios for the rocket dog to get into.

After cleaning the kitchen and putting the dishes in the dishwasher, Grillby traded his yellow gloves in for arm-length rubber ones to give Papyrus a bath. As much as the kid loved his spaghetti, he never failed to get it everywhere.

Once bathed, he let Papyrus go to play with the other kids. He walked down the hall and stopped for a moment to listen.

He smiled to himself as the kids decided that Rocket Dog was going to land on the Jupiter and become the first resident there.

"Can you guys include your brother, Sans?"

Sans looked at his dad for a moment before he huffed. "If we have to."

Frisk beamed. "Of course we can! What do you think he'll be when he grows up?"

Sans laughed. "Annoying!"

"Sans." Grillby couldn't help but smile even if the comment was a little rude.

"Nah, he'll be the greatest sketti chef that ever lived. Won'tcha Paps?"

Papyrus shuffled in. He sat down in the middle of the Legos and picked some up before trying to put them in his mouth.

"No, no." Sans reached out and took them from him.

Grillby had just turned around when Papyrus screamed. He put his hand to his forehead and groaned.

"What was this about you not bugging your brother?" he asked as he went in the room.

"I just took the Legos away from him," Sans said innocently. "He was gonna eat 'em."

Grillby nodded. "That was a good idea, then. It's not your fault your brother's tired."

"I'M NOT TIRED!" Papyrus screamed. He wriggled, trying to escape Grillby's hold.

"Why don't you two play, and I'll see if I can't entertain this little squirm."

He left the kids alone and took Papyrus to his own room. He lifted down several puzzles and set them on the floor, sitting cross-legged to help his son try to figure them out. It worked. He was close enough that he could still hear conversation from the other two and yet keep his youngest son entertained.

It seemed no time at all had passed before Grillby's phone beeped with a text message. AnnaLee and Jordan were on their way to pick up their daughter. He gave Papyrus a kiss on the skull before he got up to let the other two know what was going on.

"But she just got here!" Sans whined.

"I know. And if we surrender her now, maybe she'll be allowed to come back. Will you two clean up, please?"

Frisk nodded and immediately started to put the toys away. Sans continued to grumble a little. Instead of actually helping, he used magic to put things back in the bin. Frisk laughed when he lifted her up to get something that was under her.

"That tickles!" she squealed as his magic lightly grazed over her skin.

He put her down and winked at her. "I can lift almost anything I want."

"I bet you can't lift your dad."

The two kids snickered together as he thought about how he would go about doing that. Once all the toys were put away, he had a plan.

"Dad!" He called out. "Everything's put away."

Grillby called back. "Okay. Please help Frisk make sure she has everything she came with and go to the living room."

Frisk hadn't brought anything over, so his request was shortly met. As Grillby came into the living room, Sans' eyes and hands burst into flame.

Grillby stood and crossed his arms as soon as he realized what was going on. He didn't fight it; he had heard the girl's question. He smiled a little as his feet lifted off the ground an inch. Two inches. Three.

He reached a maximum height of five inches before Sans couldn't do it anymore. He accidentally dropped his dad, who landed gracefully on his feet.

"I did it!"

The two kids shared a high five.

"Sorry, Dad."

Grillby laughed. "You're not in trouble, Sans. Just don't think you can go about getting away with anything just because you can strain yourself enough to lift me five inches. You understand who you get that magic from and that he would be very upset if you were to get into trouble with it."

Sans nodded.

All too soon, Frisk's parents were there to get her. The kids said goodbye and hugged each other before she left.

A/N: Thanks so much for reading! I'd love to know your thoughts!