So, in honour of Toasty's much anticipated Bucket Companion Mod:
I give you this article that explains just who Bucket is in the Pandemic world. Bucket is a demi-god related to Crate. Bucket and Crate have the same father, Kratos. But, different mothers. Crate was born from Cratalia, the Crate Goddess. Bucket was born from just a regular Bucket woman. Now, you might ask "How in the hell can these objects be people?" Divinity, that's how.

Religion in Pandemic is strange, to say the least. It's general concepts stems from Norse religion, where any oddball notion goes. Seriously, we think clouds are made from the brain matter of a dead giant. Not several dead giants, mind you. Just the one. The same one from whose armpits the first mortal humans were born. This is all in the Edda, I'm serious.

But it's also worth to note that Crate and Bucket are supernatural beings, and their existence is greatly conceptual. Their forms in the mortal planes are deeply metaphorical. Crate is a Crate because he is the holder of all. He is a divine being. His body is only meant to represent him as a sentient, formless abstract. Same thing with Bucket. So, it all kind of makes sense.

So why are they so passive in the world of war and greed that is Pandemic? Why, the Epicurian Paradox, of course:

"Is God willing to prevent evil, but not able? Then he is not omnipotent.
Is he able, but not willing? Then he is malevolent.
Is he both able and willing? Then whence cometh evil?
Is he neither able nor willing? Then why call him God?" — 'the Epicurean paradox

Fact is, Bucket and Crate simply don't care. They're immortal. The ideas of anguish and suffering and human loss is something they can't relate to. They don't understand what death is. Even if Bucket were to die, for instance, he'd simply lose his mortal form. He would still exist in the otherplanes. To them, the mortal planes are simply a place of amusement. A petting zoo full of Legion, Psykers, Zombies and fanatics, all tearing one another apart in a great spectacle. A spectacle to which they are eager spectators.

History of Crate and Bucket:
Bucket is first mentioned by Crate in a joke:

"There once was a man from Nantucket.

Except he wasn't a man.

He was my brother.

His name is Bucket."

Bucket has lived for as long as time itself has existed. But due to his "tainted" immortal lineage, he's an abominable being in the eyes of the denizens of the otherplane. A mudblood, if you will. With good reason too. As his limited perception and means of comprehension won't actually allow him to properly exist in the otherplane, like any other mortal. As such, he's developed an almost autistic behaviour. Much like how certain individuals with autism suffer from an extreme influx of information and stimulus, to the point of where it overwhelms them, so does Bucket. Crate took pity on his half-mortal brother and sent him to the mortal realms in order to help him cope with existence. Putting him in his bucket home, where he left him with his toy truck and jukebox. To play in the mortal realms and avoid the pains brought to him by the otherplane.

This is also the true nature of Crate's presence in the mortal realm. As he is looking after his brother from afar to make sure that he thrives in his limited plane of existence. This also explains the strange size differences between Bucket's home in the mortal plane, and the interior that is located between the mortal planes and the otherplanes, in the outskirts of reality.

So, now you know about Crate and Bucket.

And yes, before you ask, all you Psykers do summon things from the otherplanes. That's where all the ghoulish things come from.