A/N: Featuring the headcannon of Diavolo being Mammon's sugar daddy and Barbatos secretly enjoying his company.

When Lord Diavolo requested to see Mammon to his home. The second eldest was half-expecting his brothers to be there at his office.

But to his greatest relief, they weren't there...the moment he walked into the office. He only saw Diavolo with a concerned yet relived smile and a gentle yet stoic professional look on Barbatos' face.

The demon servant had opened the door for him.

Barbatos: Mammon...We been expecting you.

Mammon: Y-Yeah...

He still didn't want to see his brothers at this moment. He knows he's avoiding them out of fear. Lower demons can call it pathetic all they want.

But he wasn't taking any chances.

He wondered why he was summoned to Diavolo's home.

Was he in trouble...?

Did he do something wrong again?

Was he going to be put on house arrest like Lucifer or locked up somewhere like Belphgor?

Diavolo: Mammon! Oh so good to see you again! You gave us all quite a fright when you vanished for two days.

Two days...Two days since the pity party. Mammon swores underneath his breath trying to forget all that had happened. But no matter how much he tried. He knew this event and his brother's insults will forever be in his mind.

Mammon: Yeah...Nice to see ya too Diavolo. Sorry for causing you any trouble...

From his apology, Diavolo and Barbatos frowned at this. Mammon flinched seeing them both glower like that. Was it something he said? Was it because he didn't address Diavolo as "Lord Diavolo" or "Young Master" like Barbatos or Lucifer always tell him too...

Diavolo: Mammon. You didn't cause me any trouble.

Mammon: Hah?

Diavolo: Don't be so stiff! Come in~! Come in~!

Mammon:....Are you sure I'm not in trouble?

Barbatos: You haven't stolen any of Lord Diavolo in a while unless you're plotting something, right?

Mammon: No...

Barbatos: Then you're not in trouble...Lord Diavolo actually wishes to speak to you which is why he required your presence alone.

Mammon nodded as he walked towards the desk and sat in the seat in front of the two. Still feeling really nervous.

Sure he wasn't scared of them but you do need to be reminded that Diavolo is the Prince of Devildom and Barbatos is his loyal servant. Even if they don't show it, they had striked fear into the hearts of so many demons. If you dare ever cross them, your fate is sealed, and not many had lived to tell the story. Mammon can consider himself lucky Diavolo has a sense of humor when it comes to him messing around.

Mammon: Really...So my brothers really aren't here...?

Diavolo: If they were snopping around. You know Barbartos would've handle the matter immediately.

Barbatos nodded still showing up that butler-like attitude. Mammon shuddered at that, remembering the times he broke into Diavolo's home trying to steal the Prince's treasures only to get apprehended by Barbatos.

Mammon: S-So...is there a reason I'm here...?

Diavolo: Yes...Mammon...For two things. First. Barbatos.

Barbatos: Yes.

Barbatos pulls out a present wrapped in black and gold wrappings while he gives it to Mammon who looked amazed.

Mammon: Ohhhh~!

Diavolo: Happy Birthday Mammon. I hope you enjoy our present.

Mammon: Thanks Lord D! Barbatos!

He opened it up quickly to reveal a stuffed yellow and black devildom teddy bear complete with horns, wings, and a tail. On the teddy bear stomach had the word "Avarice" on it.

Mammon knows he's very old for stuffed toys. But he didn't care...

Plus, there was a bonus.

Next to the devildom toy, there was a new credit card, that looked similar to Goodie, along with a note.

"The card has been activated and I put some money on it. Spend yourself something nice. But don't go overboard~!"

------XOXOXO Divaolo

Mammon: Thanks Diavolo~! You shouldn't have!

Diavolo: I felt like I should...I'm glad you like your present...because the second thing...

Mammon: Yeah?

Diavolo:....I owe you an apology.

Mammon: F-For what? If it's for not showing up at my Birthday Party. That's fine. Ya along with Barbatos were busy with your royal duties and stuff.

Diavolo: That too but no...It's about what happened at the Royal Ball two days ago...

Mammon:.....Oh.

*Flashback*

The Royal Ball where almost every demon had attended. Well, it's mostly for royals anyway. Like any other ball or party, there would be music where you can dress up and wear a mask to hide your identity.

It can be formal or not depending on the theme for celebrations and entertainment.

Most noble demons were dancing together and some were either drinking wine or hanging out with friends. Barbatos was holding a tray holding biscuits while giving them out to guests.

Lucifer: Lord Diavolo. I take it  that you are pleased with the results of the party?

Diavolo: Oh yes, Lucifer! Everything is perfect! And everyone looks happy to be here!

Lucifer: I'm glad you are enjoying yourself. Me and my brothers will be on our best behavior. I'll make sure of it...

Diavolo: I see...

Diavolo then noticed the other brothers were chatting among themselves. However...one brother was missing...

Diavolo: Lucifer...Where's Mammon?

Lucifer had a purple aurora at the mention of the second eldest. Diavolo frowned at seeing it.

Lucifer: Mammon is staying home.

Diavolo: Really
...But...Lucifer...Mammon is-?

Lucifer: Did Mammon do something again, Lord Diavolo?

Diavolo: No. Mammon didn't-?

Lucifer: You don't have to cover for him. I'll make sure he gets punished severely when we get home. Don't trouble yourself with that Good-For- Nothing anymore, Lord Diavolo.

Diavolo didn't like how Lucifer was treating the second eldest. He's aware that this could be Lucifer's pride talking but he can go overboard sometimes with his "punishments".

Lucifer: I'll see myself out. You take care Lord Diavolo.

Diavolo: Wait! Lucifer!

Before he could get the first eldest brother, many noble demons soon got in his way.

"Lord Diavolo! It's so good to see you again!"

"Let's have a pleasant chat like always"

"What's it like being the future king of the Devildom. Are you looking for a finance anytime soon~?"

Diavolo groaned. He'll deal with Lucifer later. At much he hated it, he had no choice but to be civilized with these nobles...

He just hopes Mammon will be okay...

*End Flashback*

Diavolo: When I asked Lucifer about your whereabouts. He just jumped to conclusions and assumed you did something wrong again.

Mammon: Ha...Sounds like him...

Diavolo: After he left. He started bombing my D.D.D with questions and concerns about your whereabouts. So I asked Barbatos to look around for you.

Barbatos: And when Simeon texted us on D.D.D that you were staying with him and Luke. We were greatly relieved to hear that you were okay...

Mammon:...You guys...don't have to worry about me...

Diavolo:...What makes you say that?

Mammon:...A-All I ever do is cause trouble for ya guys. I'm...just a burden and a good for nothing like Lucifer said.

Diavolo: Mammon...You are not a burden or a Good For Nothing. You are amazing.

Mammon: I am?

Diavolo: Of course you are. You're the third most powerful demon and one of the seven demon lords here in all of devildom. Anyone here who hasn't get that has to be a fool to not get that by now. Sure, you haven't snapped or tried to kill as much as your brothers. Despite how brothers see you, you're actually quite capable of many things...

Mammon: R-Really?

Geez, what's with all this praise...He wished Lord Diavolo would speak more about him earlier the last time he tried cheering Mammon up. But sadly, Lucifer told him to stop making things harder for Diavolo.

Mammon: But...I'm just a stupid scumbag that steals from people.

Diavolo: But you also keep your brothers in line....A part of me wonders...did you allowed your brothers to bully you?

Mammon:....

Diavolo: And the whole..."stupid" "scumbag" and "nuisance"...if that's how Lucifer and your other brothers really see you as...then I guess they shouldn't be allowed to see you.

Mammon:....

Another uncharacteristic frown on Diavolo's face. A very constant that this man despite his jovial attitude...can be very scary when he needs to be...

Diavolo: First forgetting your birthday. Accusing you of a crime without any evidence. Punishing you for the crimes you did not commit yet. Then allowing the other brothers to call you names and insult you...Then there's the situation when Lucifer said "You should've died instead of Lilith"...

Mammon:....

Diavolo: Surely he has forgotten that I was the one who made him started the Rebellion that day. So if he should be angry at someone. It's not you. It's me that he should be angry at.

Mammon: H-Hey! Come on Diavolo! Sure you don't think I'm a burden and I appreciate that. But...Surely, Barbatos would agree.

Barbatos:.....Actually. I don't.

Mammon: Hah?

Was he hearing things correctly? Mammon was getting confused.

Mammon: Aren't I just a nuisance to you?

Barbatos: While...It is troublesome for you to keep breaking into Lord Diavolo's home and steal his royal treasures. But...I have to admit...It does get boring when you don't.

Mammon: Eh?

Diavolo: See Mammon! Barbatos likes you! I like you! Whether you believe it or not. We care about you, Mammon.

Mammon: Y-Yer not bullshitting me are ya?

Diavolo: Mammon. I speak the truth. Lucifer may be my friend...but I see you as a good friend too. Someone to treasure. I wanted you to know. You hold a special place in both mine and Barbatos' hearts.

Barbatos: I wouldn't go that far Young Master but yes. Mammon. What Lord Diavolo is trying to say is...He is sorry for allowing Lucifer to punish you for something you haven't even done yet. He wishes to make it up to you. Plus, in my opinion, Lucifer knows better to blame you for the problems he caused and to forget your birthday like it ain't important to him...

Mammon: Really?

Diavolo: Yes! I feel like it's my fault you never got to celebrate your birthday because of the royal ball. Two parties in one day. One was a success and the other was a total disappointment. I'm so sorry about that, Mammon! It's so my fault! So if you want us to throw you a party! We can do that! Right, Barbatos?

Barbatos: I can get to work right away.

Diavolo: Sure it wouldn't really be much of a surprise. But still...It's your birthday party! You have every right to celebrate it!

Mammon couldn't help but smile at that. First MC...Then Simeon and Luke. Now Diavolo and Barbatos. Who else is next...? Solomon? Raphael? Thirteen? Mephistopheles?

It feels nice being around people who actually would treat you better and appreciate you...than his own brothers...

Mammon: Thanks Dia~! Yer the best.

Barbatos: That's Lord Diavolo to you, Mammon.

Mammon: Oh come on! You didn't bother to correct me the last few times! Ya stinkin royal butler!

Diavolo just laughed brushing it off. Mammon can call him anything he wants. He watched as a teasing smile came on Barbatos' face as Mammon huffs at the demon servant.

Besides, despite being the future king of Devildom. It felt nice getting a nickname or being called by your first name.

Most people were afraid of Diavolo due to his title and his power.

But...Mammon...

He was one of the few people who wasn't truly afraid of him. It made Diavolo feel special. No offense to Lucifer. Which is why he sees Mammon as a friend.

A very good cherished friend. 

Another reason he let's Mammon off is....well, he wouldn't mind giving Mammon some money if he needs some...

Mammon: Hey! BTW...Have you guys...told Lucifer or the others where I'm at.

Diavolo smirked and shook his head.

Diavolo: Actually...

Barbatos: We didn't.

Mammon: Hah?

Diavolo smirked grew wider. He wanted to see the angry face on Lucifer. Just seeing him get riled up amuses him.

A sight that everyone would like to see.