((Let me just put it simpler, then. >_< no matter how far out you go, there is only one Shis'm Caes. All universes are a single fragment of the Great Cycle, and each multiverse is, I suppose, a set of universes with similar traits and characteristics, and so on and so forth. There is only one ultimate beginning, but any number of things can spread out from that.))
((I really, really don't like omni-anything in fictional characters, whether it's Eru Iluvatar or G...an. Such characters tend to either dominate the story, bring up all sorts of questions of why there is a story, or both. Yes, even bound ones like Shys'm Caes. The biggest question there is "How the hell did she get bound?" and "How has she not freed herself?", which narrowly beat out "What was she smoking?" and "Who said ragnarok could dictate the origin of every frikkin' universe ever brought into contact with the RotMGverse, even if that screws over story ideas?"))
((Technically she's the original beginning. There ARE Universes that weren't created by her, but she created Creation in the first place, which paved the way for the rest of everything.
And to answer your questions:
1: she deliberately weakens herself in most fights when she's at full power in order to give the other person a chance, as it's more fun for her. She is bound by the laws she creates, and Yuri's family exploited these laws in order to fabricate a spell that prevents her from disobeying them and also stops her from unlocking the remainder of her powers.
2: See above mention of not being able to disobey them or unlock most of her powers. Also, much as her current predicament annoys her in that she has to follow orders, mostly it's just 'go kill these people', which she enjoys, so she hasn't bothered to try.
3: Nothing, she was drunk on battle.
4: Scap when he said we could just pull metaphysical stuff out of our asses as long as it doesn't contradict anything previously said.))