can she shapeshift? how powerful is she? this anon can't think of much to ask.... hmm... whats her sexuality??
Shapeshifting isn't the right word. I was serious when I said they have a culture based on plastic surgery; their biology (consisting of a thin, flexible mesh of electromagnetic metallic nodes that produce the field that keeps their plasma in shape) is incredibly easy to surgically manipulate. Like, plastic surgery is about as simple as a doctor's visit (but not, like, American ones). That's why their culture has evolved the way it has! And once they became spacefaring, once they started meeting new, visually-interesting extraterrestrials with body plans they hadn't even considered before, their culture exploded with new fashion trends, new ways for a Ssreshin to be who they want to be.
So while she can't change her shape on command, nor can the other Ssreshins, it's very easy to switch things up if she's feeling bored.
As for power, she's not, like, wildly strong or anything - she is, however, essentially a walking lightsaber. They have to wear clothes and armor made or coated in that same metal that occurs naturally in their forms. No, they don't get it from Ssreshins - their planet has a strange, mindless amoeboid lifeform that shares a similar energy-based biology. They're farmed like cattle for both excess ssreshite and plasma.
Finally: Sexuality is kind of a vague concept for her, since Ssreshins are essentially sexless, genderless people - they only started taking masculine or feminine forms after they met humans, and that, in kind, meant the humans started assigning pronouns to them. Riss uses feminine pronouns because it's easier for people to understand, and she calls herself a lesbian because she favors similarly feminine folk.