Descendant of the Overlord

I don't own Overlord or Rosario + vampire

Prolog

Ainz has spent many years in the new world so many years in fact that humanity had managed to destroy itself and thus the humanity had started again but unfortunately for the humans the ways of magic where closed almost entirely off from them and by this point Ainz had given in to Albedo's and Shalltear's intentions although it had taken them a long time to even find a possible way to ensure an heir although through this time the humans and monsters had begun restructuring their societies in accordance to the changes within humanity.

Currently

Ainz stared down at his child, a being born of the union between himself and his top two guardians Shalltear and Albedo through the use of magic Ainz had done this for two main reasons one was to ensure that a strong child was born and the second reason was to make sure that the mothers of his children didn't attempt to kill the others child granted they fought the idea at first but at his insistence the child was made as he wished and now after many years work his young boy was going to high school.

Ainz gave his nervous child a small smile well as best as he could with only his bare bones "Don't worry Sin, my son I am sure that with your training no one at the school will give you much trouble."

Albedo spoke next picking up her son in a hug as she went "And if they do tell momma and I will deal with them." only for Shalltear to rip him from Albedo's grasp with a scoff "As if he would go to you, cow… if my little boy has problems he can always go to me for actual help."

Ainz watched as his boy was once again torn from one of his mother's arms and thrown backwards only to be caught by Ainz himself and sat down with his son ruffling his black and silver streaked hair while his son stared up at him with his slightly glowing reddish gold eyes "Why do they fight like that?" earning a sigh from his father before he replied "They just love us both a lot and they are also just very jealous people in general." Sin gave a noise of acknowledgement before turning back to his mothers.

He was slammed into from the back before two pairs of arms wrapped around his eyes and two you voices rang out. "Guess who." Sin gave a small smile "Oh I don't know how about my adorable younger sisters!" and with that Sin turned and began tickling them causing the two young girls to giggle happily as they fell over.

After a minute the two girls were begging for him to stop his attack "Ok fine but only because you asked nicely." said Sin standing up straight and helped them up while Ainz watched on with pride as his children played one last time before they were separated for a year.

Although before Ainz could continue his thought process the sounds of fighting had stopped and two blurs rushed past and group hugged the teen and two kids murmuring on about how adorable they were together and how they would miss this type of family bonding causing the two kids to struggle and Sin and his father to face palm before a bus creakily came to a stop in front of them.

Albedo and Shalltear gripped their son tighter as he tried to grab his bags so he turned back to his mothers and sisters "Relax it's not like I am leaving forever…and I know I will write when I can." said Sin with a small smile.

"We will miss you Sin." spoke Ainz handing his son his bag before patting his shoulder while Shalltear and Albedo join Ainz before giving their son on last hug while the younger two began tearing up slightly "Don't leave brother we'll miss you!" Sin kneeled down slightly and hugged the two before kissing their foreheads "I will miss you too but I have too." replied Sin before he moved to the bus which opened the doors as he approached before turning and walking backwards slowly "And make sure to give my regards to the staff and Uncle Cocytus." with his final piece said Sin entered the bus and nodded at the driver before taking a sit near the middle of the bus and waved to his family as the bus began to move again.

After a few minutes of riding Sin looked to the driver "What's the estimated time of arrival?" the bus driver simply raised an eyebrow as he looked at Sin through the rearview mirror "You can sleep if you want it will be a while after all until we arrive at our destination." Sin gave a nod and leaned against the window bus after setting his bag beside him before slowly beginning to nod off into sleep.

Sin later awoke to a wondrous scent, the blood of a human and so Sin looked to the door of the bus and was greeted by the sight of a girl roughly his age entering the bus rather nervously before moving down the isle of the bus and sitting in the sit parallel to his.

"Hi n-nice to meet you my name Tuski Aono." the newly named Tuski offered her hand to him as she spoke Sin smiled and shuck her hand before replying "I am Sin Ool Gown, it's a pleasure to meet you Miss Aono." Tuski almost immediately gave an odd expression when Sin said his name Sin chalked it up to his name being odd to the humans but Tuski almost immediately went to apologize but was stopped by Sin "It's fine Miss Aono I am aware that my name is odd but then again I have rather odd parents to thank for that…feel free to call me bones if you want."

Tuski thanked him for understanding and attempted to start the conversation again "So what are you going to the academy for?" Sin chuckled slightly "My parents are sending me to yokai to make some friends…I believe that it's going well so far what about you?"

Tuski gave a nervous laugh at his question "W-well it's the only school that would accept me so I kinda had too." Tuski gained a depressed cloud over her head as she spoke earning a small laugh from Sin before the bus driver cut their conversation short by announcing that they would be approaching the tunnel that leads to yokai within the next minute so both looked out of the wind shield and waited and once they were well inside the tunnel boy were they surprised when the wall were suddenly glowing different colors before the two were blinded by a bright white light at the end of the tunnel.

Sin and Tuski blinked owlishly as the light suddenly vanished and they greeted with a rather haunted looking environment which became even more wicked once they got off the bus and became aware of the blood red sea behind a rather old looking scarecrow and to top it off the bus driver spoke one last time "Be careful after all yokai can be a dangerous place kids." and with that said he closed the door and sped off in the creaky bus.

Sin looked over at Tuski and with a playful smile said "Well the gardener has done a wonderful job with this place." Tuski laughed a little at his attempt to break the tension and followed him as Sin began to walk into the woods towards the academy.

And cut