I've seen the face of Lord English.
But really, it would be a misnomer, to say that I've seen what is really Lord English. For that matter, to say that Lord English is a he is rather stretching it, for the face we see may well be a facade built for the benefit of... what?
First things first. Lord English is the only thing inside our multiverse who is outside the Code.
I've spent years immersed in the Code, immersed in the very fabric of reality, and most of those years with the power of a god - (we all have those powers now, here, at Skaianet. But that's a tangent).
Lord English is readable enough at first glance. A chunk of code, derived from a First Guardian. Some intelligence, primitive and rudimentary but usable, and the body interacts with light and gravity and suchlike in the usual fashion. One leg is cut off just below the knee, replaced with a gold-plated peg leg.
Here's the thing, though - you can't damage him. Lord English will adapt to a threat as soon as it might kill him - faced with a gun his skin changes to deflect all bullet wounds; in danger of being frozen solid he adapts to put out his own warmth; faced with a black hole he'll gain the ability to transmit his information out with the Hawking radiation and reassemble outside the event horizon.
It gets weirder. There's nothing in his code, we've looked over it many times, that implies that he should be able to do this. No adaptivity. Only the simplest of animal intelligence. The Code just changes to deal with threats as they come, and yet Lord English, or this avatar that we call Lord English, doesn't have the reflexive capacity to change its mind, let alone its body.
I proposed, then, that maybe Lord English is only an avatar, maintained by forces beyond our knowledge, of... well, forces beyond our knowledge. "He" eats universes - maybe we live inside a computer and our garbage collection algorithm is both sentient and an abomination. Maybe the universes eaten in this way are merely being collected for further study by something, though what it would be I haven't the slightest idea. Maybe we're figments in the imagination of a handful of twentysomethings who are just screwing with us. There's no way to know.
This was not a popular proposal. Hadron certainly didn't like it - she thought I was being mystical, where "being mystical" is functionally equivalent to giving up. But once you've ruled out all the likely possibilities, it only remains to begin working through the rather more unlikely possibilities. Nothing inside the Code is supposed to let him do this, thus the cause must only be outside the Code.
We sent a probe into his maw, packaged inside a universe. First several thousand digits of pi, the mathematical axioms of Euclidean geometry, that kind of thing. Nothing happened.
All we know is that he has a mouth, and that once inside the mouth, everything stuffed inside disappears from reality.
That's why we call him a demon.