Starlight Twinkle

Base: softybases.deviantart.com/art/…
Cutie Mark: starryoak.deviantart.com/art/S…
Resources: mlp-vectorclub.deviantart.com/…
Revamp of this, which is in and of itself a revamp of this.
Twilight Sparkle and Orion/Flash Sentry's daughter (Main TFIM Canon: Orion, Quartzverse: Flash Sentry), sister to Love Letter, Pink Sunsparkle, and Moonlit Bloom (Quartzverse only).
She's usually a levelheaded mare, but she has a lot of quirks, and a bit of a problem with her impulse control. Starlight is an explorer. But not just any explorer; she explores universes. She has been exploring since she was a little filly, playing mountain climber up in the attics, discovering Uncle Spike's treasures (and getting caught), an avid enjoyer of 'The Floor is Lava', and now an explorer into other worlds. She specialized her magic very specifically on teleportation, eventually moving up from simply being proficient, but being a master in teleportation. Unfortunately, she isn't that good at other forms of magic. Eventually, she started to wonder about the concept of teleporting and portals like the one her mother traveled through into the human world, and then she found her true calling; universal exploration.
Starlight Twinkle's universal travel is founded on the spell that her mother used in 'Magical Mystery Cure'. Twilight fundementally fucked up the entire universe with the spell. She essentially brought an alternate reality directly into Equestria Prime through her magic. The spell wasn't about the cutie marks, the point of the spell was to change destinies; "From one to another, another to one". So essentially, Twilight swapped her friends out with another universe, while also giving the entire world the memories of them having always been the way they are. But the Elements of Harmony being mixed up in color wasn't mixing them up, it tried to, but the Elements of Harmony are pretty insistant on remaining constant, as harmony needs stability. So when the Elements were put on, they fixed their Bearer, clearing away the mistakes. And since Twilight is a constant, the same happened in the alternate world that the 'real' Mane were switched with at the same time.
Something that wasn't pointed out by most is that the swapped ponies are referred to by the name that their cutie mark matches.
Twilight Sparkle: Rainbow Dash, that's not funny!
Rarity: Terribly sorry, darling. I'm afraid I'm... I'm not good with the thundery ones.
Twilight didn't have enough time to stop and think about the implications of the spell, focusing on fixing it. Starlight looked at the spell and the solution Twilight made. The spell worked with her solution, but Starlight went 'what if there are multiple ways to do the spell?' and she set out to try some experiments. In retrospect, she probably should have thought it through a little more before just doing it, considering how many ways it could have gone wrong. This is a rather constant thing with Starlight; she doesn't always think through her experiments. She thinks about them a lot, but the risks aren't always on her mind; she wants to get things done for science and if she has to make the universe itself roll over and play dead for it to happen, she's going to do it. It's kind of amazing that she hasn't destroyed the universe several times over at this point.
She also kind of has a thing for weird side projects and inventions that can get a little dangerous. She sees all this super cool tech in some alternate worlds, and she goes 'I wonder how I can make it here'.  Unfortunately, she's a teleportation expert and a universe explorer, not a mechanic. She has a pair of safety goggles and a wrench and all the tools she's at least 35% sure are what she needs for the projects. She just doesn't have any clue what she's doing. At least she's not going to be creating time altering paradoxes, since she's got the know-how with the universal paradoxes.... although she found that out in one of the ways things could have REALLY gone wrong, though. She basically thought about the paradox situation, and then remembered 'hey, mom traveled back in time and caused an infinite loop, I wonder how that works'. As mentioned, she does not always think her science through to the end. She lets Love Letter live in her basement out of the kindness of her heart, even though both of them utterly despise each other. She really should kick her out, but she hasn't yet.