Leviathan:

Look, he can barely handle his favorite anime characters dying, so you? Yeah, no, that’s way too much. 

Nothing actually popped up to remind Leviathan of your mortality, it was because of Satan throwing his books all around the house that did it. 

Suddenly, it was all he could think about. How did he not think of this before? 

Leviathan is no Satan though, and he’s certainly not Lucifer. Researching medical documents and trying to think of things to keep you alive longer are a little over his head. That being said, there were some things he could do.

Leviathan dove into his own research that would be within his realm of understanding, studying that humans who have more positive mindsets and who are less exposed to depressing forms of media, may live longer than the average person. This- this was something he could work with. 

Suddenly, you were constantly being invited to his room, Leviathan having a variety of slice-of-life anime for you to watch with him, all of which had happy endings to boot. If an anime was even remotely depressing, he made sure to keep that out of reach. 

Video games? He’s keeping it safe; he’s not risking anything here. If it’s not similar to Stardew Valley, Animal Crossing, Dreamlight Valley, or The Sims (which must be on a good day), you’re just not playing it. Kingdom Hearts if you’re lucky. 

Satan:

Would do an insane amount of research 

Likely overheard the topic on a news segment about the tragically short lifespans of humans before it all clicked together.

Satan, unlike the other brothers, has never experienced death before, so while it sounds silly, he never had reason to think of you dying.

Looks up humans who had long lifespans to see how he can implement those things into your lifestyle.

Books will be littered everywhere (although that’s not really unusual, but what is would be the topic of said books- The Long Lives of Humans, Human Lifestyle for Dummies 101, The Road to Human Immortality, etc. etc.)

This is when Satan learns just how easy it is for a human to kick the bucket.

Heart attacks, brain aneurysms, strokes, seizures, cancer, the list goes on and on and it’s starting to scare him. He didn’t know humans could just drop dead. 

He’s going to start researching curses to increase your lifespan, or at the very least he’s going to make sure you’re careful as hell. 

You won’t even get as much as a cut without him being aware of it; he’s going to hover around and mother hen the absolute shit out of you. 

Try not to get too annoyed with him though, it all stems from good intentions. 

Asmodeus:

He’ll be damned if his shopping partner for life is going to die on him.

Asmo isn’t stupid; if anything he’s pretty emotionally aware. He's known for a long time just how short the lifespan of humans is.

But still, it came in the form of a nightmare. One where he couldn’t save you, despite giving his best efforts. The way you died was tragic, long before your life should have ended. 

This sent Asmo somewhat into a frenzied state trying to find things to keep you alive once he woke up. 

Vitamins, vitamins, vitamins

Humans benefit from vitamins, right? Surely you’d benefit from Devildom vitamins then. If it’ll increase the lifespan of a demon, he sees no reason why it wouldn’t increase your lifespan. 

Of course, it really only gives you nicer nails and shinier hair. 

He’s 10x more intense with your morning and night routines. 

He will be unloading all his facial creams on you, and telling you the benefits of each one and how it might add a few years to your lifespan. 

You want to stay up late at night to finish homework? Maybe watch a movie? Yeah, no, not on Asmo’s watch. 

Your ass is going to bed every night at 10pm, right along with him. You do realize you’ll be getting exactly 8 hours of sleep each night, too, right? 

Beelzebub:

Regarding his trauma with Lilith, it came as no surprise when he started to fret over your well-being. 

Poor Beel saw an article that discussed how tragically easy it is for a human to die. The cherry on top? How they could die from simply overeating. 

Overeating isn’t a concept Beel is overly familiar with (because to him, it’s never overeating), and while he knew most people couldn’t keep up with his eating habits, he didn’t think it could actually cause harm to a human, let alone kill them. 

Grocery trips are now a more anxiety-inducing event. 

He’s suddenly paranoid that any of the Devildom food could and will kill you. Are you allergic to anything? How would you even know? 

What if one day he serves you his favorite boiled dragonhead and you just drop dead at the dinner table?? No, that will never do. 

There’s a list of Devildom foods that he knows for sure you can have without dying, but then comes the issue of portion control. How much is too much for a human? 

Beelzebub swore he would never lose another loved one again, and it’s a promise he intends to keep. From now on, you will only eat what he deems safe. 

You want to try a new food in the Devildom that you’ve never had before? You better get some seriously good convincing skills if you want him to cave in. For someone who only ever thinks with his stomach, he’s surprisingly stubborn. 

Belphegor:

He’s still plagued with nightmares about Lilith, especially since he still thinks it’s his fault. Tack that on to the way he blamed you and the rest of the human race for it? The man is walking trauma. 

 Like Asmodeus, this was brought on by nightmares about you dying. Different from Asmo’s, however, you usually died by his hand. Naturally, considering your tumultuous history. 

Belphegor, unlike his brothers, takes a different approach. He just doesn’t approach you at all. 

What better way to keep your lifespan long than by staying away from you altogether? 

Is it something that he wants? Of course not! But how can he trust himself to never hurt you again? To never kill you again. 

He can’t. 

So, he locks himself away in his room, sleeping most of the day or just avoiding the areas you normally like to lounge. 

On a normal day, almost everyone in the household, including yourself, would notice this behavior change. However, since you’re now being cornered by all the brothers and their concerns about your lifespan, it’s easy for Belphegor’s absence to slip your mind. 

This hurts Belphegor, but at the end of the day, he believes this is for the best.

Lucifer: 

Lucifer didn’t need a reminder of your short lifespan; if anything, it’s something he’s thought plenty about. 

Lucifer has trauma, we all know that much. After Lilith, he’s absolutely terrified of losing another loved one to something outside of his control.

And your lifespan is not something that’s out of his control. At least not how he sees it, anyway. 

If you thought he was overbearing or overprotective before, brace yourself. He’s going to step it up several notches. 

No excess of junk food, no more pulling all-nighters, no more sitting around the house gaming all day, and definitely no more overexerting your use of magic. He’s no fool, he knows the toll your magic could eventually take on your body. 

Honestly? He wasn’t this bad until his brothers started to panic about your mortality, and though Lucifer told himself he was above such nonsense, he quickly found himself taking all the precautions they were taking (and then some).