Forgot one other thing to mention: Angel's blood. Picture above is a Prinny, normal and Takuma who is a red Prinny. Check information for both things.

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"Stop it!" Tenn yelled.

Never once did he ever expect to harm a fellow angel, all to protect Riku. 

For whatever reason, they thought of his little brother as some kind of monster. When they called him a monster in front of Tenn though, he had enough and attacked them. Something that is extremely sinful.

It was punishable. If you were lucky you'd simply be banished from Celestia and doomed to be a fallen angel sent to the Netherworlds. Never to return. 

He didn't care what happened though, as long as Riku was safe. But what he didn't expect was to see Riku as well harm another angel to defend him from them. The other angels had the right to fight back since they had attacked first.

The Seraph wasn't pleased hearing this, saying that none of them should of attacked each others, verbally or physically. But since the twins had attacked other angels they were banished as punishment. 

Later when Tenn asked Riku why he would attack them too, he never forgot his answer.

"Heaven or Hell, I want to be with you Tenn-nii. Even if I might get punished too" Riku replied with a smile.

. . .

Their outfits were no longer that of an angel's anymore either, once they became fallen angels, their outfits were automatically changed to ones fitting for demons. Tenn started acting more like a demon toward others, except for Riku. While his brother continued acting like his sweet and innocent self.

After their fall from Celestia, they had been struggling to figure out how everything worked in the Netherworld they landed in. Fortunately, two noble demons found them and took them in. Tenn was reluctant at first to trust them, but they didn't have much of a choice. They needed somewhere to stay. 

Thus began their new normal lives. Well, as normal as it got.

. . .

"Tenn-nii! I'm bored!" Riku whined.

Currently he was laying on a Prinny he had gotten from Ryuu, who was the dragon demon who took them in. The other demon was Gaku, who was a vampire. Both were powerful demons.

His Prinny was unique in two ways. One, it wasn't blue like the others and instead red. And two, it caused much more damage when thrown. He had once tested the damage it could do by kicking it through a window.

It blew up the window and the entire wall.

After they had healed the Prinny, he decided to only use it when absolutely necessary. So he stuck to carrying it around and taking good care of it. He also named it Takuma.

"What do you want to do?" Tenn asked him, taking his headphones off.

"Hmmm..I don't know. Demons live such carefree lives, it's a lot different from Celestia!"

"They're all sinful. Their everyday activities are all crimes. But we can't really complain since we sinned ourselves and basically demons now" Tenn huffed.

"Tenn-nii, have you noticed that they don't treat Prinnies well? I take good care of Takuma, pay him well and give him sardines" 

"That's how things are" he replied, patting Riku. "Want to go bug those two?"

"Okay!" Riku smiled, hopping off the Prinny just to immediately pick it up. 

The dragon said it was to protect him since it was the most powerful Prinny he could find when he first gave Riku little Takuma. Though he barely used him for fights because he wanted to learn how to fight for himself. Which was a bit of a slow process, but he managed.

It didn't take the two very long to find Ryuu and Gaku talking in the living room. Their house was like a luxury villa. Most times Tenn would find Riku outside by the pool relaxing. While the two adults were normally inside somewhere talking. 

For two powerful noble demons, they weren't very interested in fighting for more wealth or power. To Tenn it seemed like either could possibly have a chance to fight for the title of Overlord. But they weren't interested in that either. It was just a waste of time.

"Hey Ryuu" Tenn greeted the dragon demon. "Old man.." he said, looking to Gaku.

"Stop calling me that brat" 

"Then stop calling me brat, old man"

Riku and Ryuu stood by and watched as the two began fighting. It was a daily occurrence at that point. Tenn's attitude had seriously changed since their fall. But Riku seemed completely oblivious to it. They let him believe Tenn was still an angel. To him it was just like Tenn was in a bad mood and it was nothing.

"Hey Ryuu I heard a demon earlier say some strange locations" Riku said.

That got Gaku and Tenn's attention.

"Huh? What locations?" Ryuu asked him.

"Umm..the Forest of Eternal Suffering, Cliffs of the Deepest Despair and the Bridge of Sunshine and Bliss" 

"What the hell kind of places are those? They're not even real!" Gaku quickly responded.

"Is that why they said the bridge was made of graham crackers?" Riku tilted his head.

"Riku..don't believe everything you hear" Tenn sighed.

Riku seemed confused about them disclosing what he had heard wasn't true. Then again it seemed kind of out there. Especially the bridge. How would you even make a bridge out of graham crackers?

"Oh yeah, I also saw a weird Prinny! It was talking really fast. The Prinny claims it was on a 'natural high'..?"

The three stayed quiet, thinking of something to say about that. What was with Prinnies? They said the weirdest things. 

"...Yeah..sure it was.." Tenn shook his head.

Just another normal day. Honestly, they wished something interesting would happen.

. . .

"..I was sent here for a reason. I just need to find the right demons to trust..."