Rias's Pet and Protector (Demogorgon and Highschool DxD)

The Fire Bird

A few days have passed and Rias has been acting weird lately. She stares off into space in deep thought and this behavior worries Demo. 
The ORC club room is empty besides for Rias and Demo. Rias is leaning on her desk in deep thought again and Demo can be found eating some meat. After a little bit, Rias lets out a big sigh that sounds like she's depressed. Demo notices this and stops eating and walks over to Rias. Rias has her head down not noticing Demo is in front of her till she feels something rubbing her head. She looks up to find Demo rubbing her head with his claws and having a worried expression. Rais then gets off of the desk and hugs Demo tightly.

Rias: "Why? I don't want to marry him! Why did they choices this for me? Out of him of all people!" she yells while nuzzling into Demo's chest with some tears in her eyes.

Demo hugs her back knowing what she means. He knows who she is talking about and Demo hated him a lot.

(FlashBack)

A few months have passed since Rias rescued Demo and they can be found playing outside in the Gremory manner. Rias and Demo running through the grass having so much fun. But soon that was interrupted by a male voice.

???: "Ahh Rias, my soon beloved," a man said "Riser has come to see you"

Rias: "Riser, what are you doing here!?" she said with venom in her voice.

Riser: "Riser's parents came here to discuss our marriage and brought Riser along"

Rias: "I WILL NOT MARRY YOU"

Riser: "That's too bad" he turns his head to Demo. "What the hell is that thing?"

Rias: "This is Demo if you should know"

Riser: "So you got yourself a pet. An ugly one at that. Mind if I pet it" he says but not as a question as he goes on and tries to pet Demo.

As Riser's hand got closer to Demo's head Demo reacted with opening his mouth and bitting Riser's hands clean off causing him to back off missing a hand, but soon Riser's hand grows back.

Riser: "YOU DARE ATTACK RISER PHENEX" he yells as he strikes Demo causing Demo to fall on to his side. 

Rias: "Riser stop your hurting him!" she yells.

Riser does not listen and he shoots a fireball at Demo hitting his back and making him screech in pain as demodogs to not like the heat. Riser is seen laughing as he watches Demo cry out in pain. Soon Riser walks away still laughing while Rias goes down to Demo's side and hugs him while crying. Soon after hearing the cries of Rias Sirzechs and Venelana her mother come out and see Demo in pain and Rias crying.

Venelana: "Rias, what happened?"

Rias: "Mother, Riser attacked Demo and shoot him with fire," she says with tears in her eyes.

Sirzechs: "I will take Demo to go heal him," he says while picking up Demo and heading inside.

(Short Timeskip)

Demo can be found asleep with Ice surrounding him created by Grayfia to stop the burning. You see, creatures from the Upsidedown like the cold and are not adapted to heat so well. Even though Demo has been living in hell his body is still not used to extreme heat.

Grayfia: "He will be fine for now. The ice should overcome the burn but there will be a mark. But may I ask, what happen?"

Sirzechs: "Yes, Rias, what happend?"

Rias: "Well, Riser went to pet Demo without confirmation from me and Demo bit his handoff. Riser's hand grew back and smacked him and shot fire at Demo burning him. He was also laughing while hurting him" she said with tears in her eyes.