Good gals, or bad gals?

Terra- Rogue

Anyone who was reading Teen Titans in 1982-1983 must have had one look at Terra, a sarcastic antagonist-turned-object of-Gar-Logan’s-affection, and thought, “ahhh, this the Titans response to the X-Men’s Kitty Pryde.” She was clearly conceived as an American teenager, but the PTB at the time noticed that a similarly enabled character, Geo-Force, had been established as a prince of a small European nation. So —presto!— she’s also the illegitimate daughter of Geo-Force’s dad.

But when the Judas Contract storyline rolled around in 1984, it was revealed that Terra was bad news; the character was intended by creators Marv Wolfman and George Perez to betray the Titans on behalf of Deathstroke, for whom she functioned as jailbait (a plot point that would never go down in today’s climate). She dies unredeemed during the final confrontation of that storyline: no last minute change of heart saw Terra coming back to the good guy’s side. Another iteration of Terra saw that a nice girl had been turned into the original’s doppelganger…or some shit. Apparently, yet another has recently emerged.

As for Rogue: the character was initially portrayed as a middle-aged antagonist who absorbs Ms Marvel’s abilities. But creator Chris Claremont cottoned to Rogue, possibly because he enjoyed writing dialogue phonetically (“AH CAIN’T BUUUH-LEEV HOW MUHHCH POWAH AH’M UHHHBBBBSORBIN’”) and then reformed her into a teenage X-Man. She’s been a fan favorite and mainstay of the X-franchise since.

Commonalities:
Both were introduced in a manner where you could not be sure what side of the fence they were on. Subsequent iterations of Terra may have been characterized similar to Rogue, for all I know.

Differences:
Their abilities differ: one is a geokinetic, the other siphons superhuman powers, energy and assorted attributes. And after Rogue was introduced as a middle aged redneck, she quickly became a key X-Man, whereas Terra has come and gone as a clone or something.

Alternate histories:

TE: A troubled teenage girl with vast geokinetic abilities named Tara falls in with a criminal mastermind and attacks the Teen Titans and their ally Hawkgirl. After seriously injuring Hawkgirl, Terra reforms and joins the Titans, with whom she has remained since.

RO: A troubled teenage girl with vast mutant siphoning abilities named Anne-Marie falls in with a criminal mastermind; taking the codename Rogue, she infiltrates the X-Men, betrays them and is killed in combat. Another, benevolently inclined young woman with Rogue’s appearance and abilities has since emerged and worked with the X-Men sporadically.