Lara-Su is Knuckles' and Julie-Su's daughter from the future timeline known as Mobius: X Years Later. She was initially at odds with her father, who refused to allow her to become a Guardian. Eventually, he relented however, only for that future to be warped almost beyond recognition by an alteration of history from King Sonic. Lara-Su and a few others recalled the rightful timeline, and together fought the despotic King Shadow, Lara-Su herself ended the fight by imprisoning him with Chaos Control. Serving as a Guardian for five years, she also became a member of the Future Freedom Fighters when Shadow returned.
Vector's son, Argyle, may have been interested in Lara-Su in the unaltered timeline judging by how he wished to dance with her at her Unveiling, and Lara seemed to also be interested in him in both timelines judging by how she was happy to dance with him and in the alternate timeline called him her "good friend" and was shown to be quite comfortable being in close contact with him. She also showed a hint of jealousy when Belle D'Coolette began to flirt with him.