God this is long. :/
It's a very rare day indeed when Shinku would be forced to fight against anyone. Despite her violent slapstick moments, she is, in fact, the least hair-triggered or aggressive of the dolls, and takes her father's words very seriously (he once instructed that none of them should ever truly harm another human being). To that point, Shinku will NOT initiate a fight that doesn't concern Barasuishou or Suigintou or Kirasuishou. It's not in her nature. She will sooner walk away than allow anything to escalate further.
However, threatening her family is a different cause--she will defend herself, and them, to the best of her abilities. As well as her medium.
Shinku, as a Rozen Maiden, has very versatile powers and abilities. Tier-wise, she can match or prove superior to Suigintou, one of the deadlier dolls, Kira and Bara withstanding.
Her basics all lie in her rose petals. She can summon them at will, and they will allow her to do any number of things. Floating, shields, a form of telekinesis (shaping them into cushions, razor-sharp knives, or a pure wall of force)...they are not limited in that respect, either. She can also "awaken" seemingly inanimate objects, and beckon them to fight in her stead, as well as "purify" objects that were enchanted against her.
She also wields a cane. Which is small and adorable. And cuts like a sword. And is just about as sturdy.
She herself has blessed stamina and durability, for a china doll. And we actually mean versus strikes the likes of which would break bones and rupture organs. Apparently Rozen was able to make each of his daughters into something of class, refinery, and shounentastic ability.
All of this amplifies considerably if Shinku is in someone's dreamworld, or her own N Field. There is also Holie, Shinku's artificial spirit, who takes care of her and typically chooses the "servants" to which she will form a contract with. This is not Holie's only function--it's capable of anything Shinku herself can do, and actually can somewhat amplify her power.
This is a bit tricky, and I totally have to apologize to Light because I realized THERE ARE LIMITS THAT I OVERLOOKED. But. Here's the skinny: The medium is there to allow Shinku access to her full abilities. In shounen retard terms, they allow Bankai/Cursed Form/Level 2 Jinki/True Form. The catch is, this relationship is totally beneficial one-way, only--at least on paper. If the doll so chooses, they can give absolutely NOTHING back to the medium, and even use up that medium's life energy until they die. They are a battery, and little more. This can change on some fields.
IE: If the medium is present in the N Field, that bond (ring) will allow them some method of protecting themselves. The same would imply even stronger if the medium is in their own world of dreams. In the real world, however, they are indeed sitting ducks. This is covered somewhat in that all dolls have a sixth sense for when their medium is in true peril. In a sense, the medium can tell when the doll is in danger as well, since any use of powers will stress the bond, which is shown by the ring getting excessively hot and glowing.
Pertaining to that stress, there are several ways the bond can break. Overstress will cause drain on the mediums part, typically critical (por ejemplo: Hina Ichigo almost killed her medium in a fight with Shinku). There's also the possibility of the bond breaking on its own from extreme overuse, in which case the contract's nullified and typically the medium will not see the doll again (Jun is an exception, since his heart as a human being grew three sizes over his time with Shinku, therefore his bond did not vanish indefinitely). The doll can also nullify the contract themselves. The other definite way is actually losing to another doll in the Alice Game, at which point their Rosa Mystica is taken, and the bond dissolves.
Shinku rarely lets her guard drop. She berates, nags, kicks, and pouts. But rarely do you ever get to see her display something other than haughtiness or that sense of absolute superiority. It's her one, natural armor.
And Suigintou cracked it completely.
In a big way, it is more Suigintou's fault than Jun's that she views the Alice Game as something to actively loathe and despise. Because she was the first real "casualty" of the Alice Game, at Shinku's own hands (with Jun's assist). And it is later made very apparent in Traumend that Suigintou's death horribly upset Shinku. Suddenly, the game was very real, and very, very horrible. For all their infighting, there was no real ill "will" toward Suigintou--Shinku still thinks of her as family. Just…very homicidal family.
And she emos about it. She has nightmares about it. When she finally meets Suigintou again, she breaks into tears over seeing her, and apologizes for years (a century?) worth of antagonism. This is the fourth time we see Shinku's true feelings in a big way. At this point, she knows that the Alice Game is a cruel fate handed to her and her sisters by a father she loves and adores unconditionally, and it tears her up inside that she would have to commit to such a contest.
Shinku vows to allow her sisters (those who feel the same way) a different path in life to the best of her ability. Of course, she gets little choice in the matter, thanks to Barasuishou and some other noisy outsiders with a hefty grudge.
Thankfully, Rozen himself decides to speak up and give Shinku an alternate path to all the violence. Otherwise, the next family reunion was going to be quite stressed.
There's also the hinted possibility of those fallen in the Alice Game being able to be brought back, but time (and the manga) will tell. man, active canon is WEIRD how do you people do this?
In the meantime, Shinku won't be initiating rounds of the Alice Game on her own. That much is certain.
This is what you call a screwball. Camp did not fit in the equation. The equation was Find That Damn Rabbit, snag some Rosa Mystica, pimp-slap Souseiseki, ????, PROFIT. And if it was in the equation, it sure is out of order.
But her she is, Pismo Beach and all the clams she can…wait.
I mean Camp Fuck U Die and all the gorillas that can wait on her. The problems?
Immediately, Suigintou. This is not the Suigintou that Shinku knows (and since Shinku is post-Traumend, she's actually had the chance to LOOK into Suigintou's mind. So Shinku knows of Megu and what Suigintou's capable of when truly motivated). This is a bitter and dispassionate Suigintou, fresh from a Father-like revival, and out to stick feathers where the sun don't shine. Suiseiseki is without a medium, and likely a means or will to really defend herself, and Shinku does NOT want to endure the pain of losing someone else ever again. So dealing with Junk is truly a kid gloves occasion. If her own pride will allow it, Shinku intends to attempt to make amends with Suigintou and help her see reason.
In the meantime, that becomes a hurdle because Junk has no qualms about killing Shinku, and anyone that gets in the way of that goal. Light was, unfortunately, a victim of circumstance. That hasty contract was one needed because without it, Light would have been severely, if not critically, injured. On a secondary note, Shinku knows very little about the campgrounds, the people within…and many of them seem downright strange. Light, on the other hand, seems to know his way around certain people. So this could prove to be a much more beneficial than the typical contract.
Does she like Light? No. He's no Jun. Shinku shows an alarming sense of innate perception in canon, being able to read Jun, Nori…almost everyone, right down to the letter. And it doesn't take much to know when someone is smiling only on the outside. She sees that Light has many, many sides to him, and that he's quite a special lad. Just how MUCH is beyond her keen at the moment--but nothing a trip into his heart with Suiseiseki wouldn't fix (if she DEEMS him worth that, after all).
At the same time, there's no hatred. She takes the contract quite seriously, and will defend him to her last breath, if need be. Letting him KNOW things is another matter, but that's Shinku being guarded, poker-faced Shinku. That includes against Suigintou's medium, Dietrich. Who…worries her. He's charming and polite and most importantly, Suigintou ACCEPTED him. She and sister dear will have to discuss that. This medium taking an interest in the Alice Game is apparently a rare feat.
This means Shinku is doubly on her guard, especially since Suiseiseki is here, and possibly in harm's way without a medium (which eventually Shinku will badger her on because something. Rotten. Denmark. Etc).