Satanine is the overseer of the Hell Dimension but no one knows how that came to be as it's just a little...creature of some kind that doesn't seem to have any conscious or reasoning ability. The creature just does what it does and just so happens to rule over hell and have access to all kinds of demonic powers and abilities. It pops up anywhere there's sin or going to be sin, or someone says "hell", not knowing that they just summoned the worst entity to ever exist.