What is 'SimAlley' and her YouTube channel?
Since 2017, 'SimAlley' has made various types of content mostly centered around Minecraft (though she has done let's plays of other games as well). During the past 7 or so years, she has taken on different personas and characters, including changing her channel name temporarily to those names. Name changes include: SimAlley, The Sheepie Queen, Dust Bunny, Alleyverse Central, and even just her own name.
The most notable character which is not one of the channel namesakes is Red Diamond (who is a queen like figure in relation to a fan made steven universe OC / gemsona). Red Diamond also has a collection of underlings which she considers to be her family.
There is also DarkAlley (the personification of her own doubts and self-sabatoging efforts). She is a meta danger to the channel and all characters.
Opal the Dust Bunny exists in the same timeline where the Flesh Collective was introduced (an invasive alien species) She was corrupted.