So, this turned out a little darker than planned. It went from happy fluff to comfort fluff. Oh, well...
For those of you who don't know who A and B are, I refer you to Death Note: Another Note. You can Google the characters, or you could read the novel (I advise the latter, it's really good!).
Enjoy!

"Mello, stop. I said stop. Mello, sit. Mell- Ah!" Matt could barely avoid the book from hitting him square in the face. "Alright, that's enough." He tried to grab Mello's arm but was instead shoved into the wall. "Au!"

"Stay out of this, Matt!"

"If I do, you'll kill Near!"

"Damn right I will! I'll throw every single one of these books in his face!"

"You'll have to get through this door first," came Near's muffled voice from his bedroom. "I've already alerted Roger. I'd better run, if I were you."

"Never!"

"He might report this to L."

Mello froze.

"What would L think of you? This just might be the last drop. He might kick you off the list."

"You…"

"Leave now and we'll both forget this happened."

Mello clenched his fists and stared at the ground. "I'll make you pay for this," he muttered. He stormed off and Matt did his best to keep up with him.

"Mello, wait!"

Mello stormed into their room and shut the door in Matt's face. "Ouch! Mello!"

When Matt opened the door, Mello was already taking out his anger on the bedroom interior. A pillow flew through the air and knocked a lamp off the desk.

"I will kill him! First I'll suffocate him, then I'll stab him, then I'll burn him, then…"

Matt sneaked past Mello into the bathroom and started running a bath. It had worked before, maybe it would calm Mello this time, too. Matt made sure that there were enough bubbles for a person to disappear in and he nearly chocked on the sweet scent. Then, last but certainly not least, he added some rubber ducks. Although, "some" might be an understatement. He himself liked to call it a "quack-ton". The bath was overflowing with the bright colored toys. Matt had collected them from wherever he could find them. He had been sure there'd be a moment he'd need them to restore Mello's sanity. That moment was now.

Matt peeked around the corner of the bathroom door. It looked like there had been a hurricane in the bedroom. In a way, there had been. Mello was sitting on one of the beds, hitting it with a pillow as if the bed was Near himself. His face was red and his mouth created an endless rant. Matt grabbed his friend and dragged him to the bathroom. Mello wasn't even registering it. He was too lost in his own anger. "…and if L had any brains at all…"

Matt guided Mello to the bathtub. Mello's subconscious made him instinctively undress, so that he wasn't aware of what he was doing until he had lowered himself in the water. "What the – Matt!"

"You need to relax, or you'll explode. Look, I added extra rubber ducks… Mello? Wait, don't-" Matt had to run out of the bathroom to escape the ducks flying in his direction. Why did Mello have to throw everything at him? "I'll see if I can find you some chocolate. Just stay here, okay? Stay. Just stay. Stay right…"

"Matt!"

"I'll be right back!"

Matt was carrying every chocolate bar he could find in Wammy's House. If only it was enough to appease the Angry Mello. When Matt entered the bathroom, Mello was playing with some of the ducks. He juggled them, or shot them with an imaginary gun, or dropped a bomb – his hand – on them.

"Mello?"

Mello was in the middle of pretending one of the ducks was a rocket ship. He dropped it with a splash.

"Mello, I brought chocolate. Is the water warm enough?"

Mello merely nodded and rested his head back.

"Are you feeling a little better?"

No response. Mello opened his eyes and stared blankly ahead.

"Mello?"

"I can't take this anymore, Matt. There's no point in it."

"In what?" Matt dropped the chocolate and knelt down next to the bathtub.

"This. I'm never going to be L. Near will always be better. So, why am I still trying?"

"Because you're stubborn as hell?"

Mello grinned. "That's true. But that's not the reason. You see, if you give up on something, what would that make you?"

"That depends…"

"A loser, Matt. How weak would I be if I were to give up on this whole thing? I wouldn't be able to live with myself. So I'm stuck. I'm stuck between never being L and never having another goal in life. And that makes everything so meaningless."

"Stop it."

Mello looked over at his friend. There had been something about his voice. Something had made it sound different than before. And it wasn't just his voice. It was in his eyes, too. Matt's entire face was dominated by one emotion: fear.

"Matt?"

"Don't do this, Mello."

Were those tears in Matt's eyes? Mello didn't know what to say for a moment. "Don't do what?"

"This."

"What?"

"This!"

"What?!"

"Turning into A!"

Mello blinked a few times. He frowned. "What are you talking about?" he asked quietly.

Matt wiped away a tear and took a shaky breath. "You're acting just like A did before… before…"

Finally, Mello understood his friend's fear. It had been Matt who had walked in on A's dead body. Years later it still gave him nightmares. Mello had first blamed A, then L for Matt's pain. Perhaps that's why Matt always played such violent games. Maybe he was trying to make A's corpse just one in many.

"Matt… Are you stupid? I would never do that to you."

Matt wiped away one tear after another, but he couldn't keep up with his eyes. "I'm sure that's what A said to B, too."

"Matt, no. Shit, I've just been having a hard day, okay? I'm overreacting. I could never do that to you. Matt, look at me. Matt."

Matt kept his head down. He didn't want to cry. He didn't want his friend to feel this way. He didn't want to lose Mello.

Mello grabbed a pile of bath foam and placed it on top of Matt's head. He added a rubber duck as the final touch. "How can I leave without having tried every possible method of bothering you?"

Matt looked up and the duck shifted on his head, but it didn't fall off. "You have to succeed L. Because if Near does, nothing will change and there will be more A's. And if B does…" Matt shivered and the duck fell. "If B gets in charge, I'm out of here."

"So all I have to do is beat Near and B and reform Wammy's system? No biggie."

"I know I make it sound simple, but…"

"Matt, I'm serious. This is easy. I'm smarter than Near. I can beat him."

"And B?"

"B is a nutcase. Haven't you heard him muttering about 'running away' and 'killing them all' and 'setting fire' and 'numbers' and 'dolls on walls'? I heard he's changed his name to BB, 'Beyond Birthday'. Beyond bullshit, if you ask me. All he can think about is avenging A. He'll go insane soon, I tell you. He's no competition."

"And if it goes wrong? If you don't succeed L?" Matts eyes were once again filled with fear over what his friend would answer.

Mello leaned over the edge of the tub. "Shall I make you a promise?"

"Please."

"Fine. I promise you that under no circumstances I will leave this world before you do. Understood?"

Matt nodded and pulled Mello into a hug.

"Matt… choking…"

When Matt let go, he seemed a lot calmer. "I brought some chocolate."

"Now, that's why you're my best friend."

Matt handed Mello his chocolate and sat in silent content as the bath foam dripped down his face. He knew that this would be the one promise his friend wouldn't break.