Superpower help

So I got a new story idea. It's where superpowes are pretty commonplace, but anyone who has them is forced into the custody of the government, to create task forces. My story revolves around a brother and his sister, who both have powers but don't particulary want them. They will think they're cool and all that, but feel that working for the goverment isn't in their interests. The brother, I've decided, will have superspeed, but I'm really stuck on the sister. I want her to have a power, but something opposite to her brother. I have considered power over the weather but I'm not really sure. So, any help would be very useful.
Thanks,
Stature

Well, the only real opposite to superspeed would be slow-mo but I don't think you would like that. But superspeed is more of a defensive power/ it doesn't deal with attacking more so getting out of the way. Perhaps the sister could have super strength or a power where its primary use is offense.

Well, super-speed can be an offensive power as well when it comes to attacking quickly -- not to mention, people with super-speed effectively have to be tanks to withstand the amount of force coming at them head-on when they're running. So they'd have a fair amount of offensive potential and defensive power.

I would, personally, shy away from giving the girl something completely opposite to her brother and instead maybe look at something like little opposites, e.g., her brother having a physical power and her having a psychological one, or her brother having an intrapersonal power (affecting himself only, no one else can have super-speed even if he's touching them) and her having an interpersonal power (affecting other people, constraints depending on what kind of power it is). This could also lead into some interesting personality differences, if the two of them are confronted by these little things everywhere they turn.

Or, as TigersMoon said, you could go for the sister having a primarily offensive power instead of a primarily defensive power, or even an environmental power (such as atmokinesis, which you mentioned) -- honestly, as I see it, it's up to you and your characters, and what kind of images you want to portray in this storyline. Every choice you make will have an effect on how your readers see your treatment of the characters.

hmm, an interpersonal power could be interesting. Like, telekinesis and telepathy, where it is much better for her to stay away from the fight?

Even with something like telekinesis and telepathy, there could be constraints on her power level that require her to stay closer to the fight -- or even in the fight -- and she'd have to improvise. That could lead to some really cool ideas on her end, having to think of ways to defend herself while simultaneously staying on the offensive to keep the fight going in their favor.

Not to mention, if you gave her a physical kinesis power like pyrokinesis, that could be a lot of power early on that could go to her head (and create another interesting character type).

I think right now a lot of your focus is on "how do I keep her out of the fight while still giving her awesome powers", and if the majority of your novel is going to be conflicts and such, it's going to look like they're all (physically, at least) resolved by the brother -- that is, it's going to look like you, the author, don't think that the sister would be able to handle things even though she has awesome powers. That's going to take a lot of thought and consideration, especially since you have two people of different binary genders as your main characters.

Do you know Quicksilver? I think a good opposite to Super Speed would be the ability to slow down time.

I thought about perhaps manipulating darkness into concussive blasts, and being able to create forcefields. As a result, she feels uncomfortable in direct light, and also fatigues easily due to the amount of energy. I think perhaps have a "dark dimension" type of thing might work, because she could summon avatars to fight for her?

Actually, now that Reise mentioned Quicksilver, it occurs to me that if you do end up with this superfast character, as well as giving his sister telekinesis powers; that would be very, very similar to the Marvel Quicksilver and Scarlet Witch.

I like your idea of summoning avatars though. That sounds interesting.

Yeah, I'm trying to stay away from Quicksilver and Scarlet Witch. Also, I think a reality warper (who Scarlet Witch is) is quite a difficult concept when it is not portrayed in a comic. I read a lot of Marvel, and a bit of DC, and I can't think of any characters linked greatly to darkness other than Cloak, and his main power is teleportation.

If you're trying to stay away from Quicksilver and Scarlet Witch, you're already halfway compared with "brother of a brother/sister duo having super speed". You're even closer by having the sister be a distance fighter, because that is Scarlet Witch's general power class is "person who messes you up from a distance".