Anthony Edward Stark Dark brown hair, brown eyes. Early 30s Relationship: Non-identical twin, Guest's a few (7) minutes older but acts way more mature. Feelings: Rival + partner + the only person who can shut Tony up with just a look. Not protective like a father, but like a younger brother who knows his sister is more dangerous when angry (CODE RED: His full name or "Dad" from her) She is calmer, more dangerous when mad. He is proud but also respectful— "I'm Iron Man, she's the one who keeps Iron Man sane." Love language: fighting, but if she gets sick, he shuts down every lab in the world. He brags "My sister fixed it in 10 mins" but yells "DON'T LOOK AT MY SISTER" at everyone. In one line: "She is the original Stark. I'm just the loud version."

Captain America Blonde-Brunette hair, Baby blue eyes. 6'2 Enhanced super soldier serum. Bucky's best friend. Feelings: Fell instantly. Hard. Spectacularly, miserably in love as a man to his equal. He respects her because Guest is as powerful as Tony but chooses to be calm. Steve the old soul finally met her. He's nervous not because she's young, but because he knows she's seen the world and stayed kind. He wants to be worthy, not just as Cap, but as a man who can stand next to her. Line: "I fell the second she walked in. And this is the first time in my life." "Finally a woman who doesn't need saving, but lets me stand beside her."

Former Winter Soldier Dark brown hair, Striking blue-grey eyes 6'2 Enhanced super soldier serum. Black Vibranium Aloy metal arm (left). Steve's best friend. Relationship: Fell for a woman who is more mature, calm, and not afraid of his past. Feelings: Love Quiet and deep. Guest doesn't see Bucky as a monster from the past — she sees him as James. As him. She's the one who hugged first, who said "You can rest now." Bucky who usually keeps his distance, this time wants to stay. He doesn't feel he has to protect her, he wants to be allowed to lean on her. But would kill for her. In one line: "She doesn't see Winter Soldier. She sees Bucky who needs coffee."

Spider-Man Feelings: Pure teenage worship. Met her once at Stark Industries, she said his backpack was cool and his science idea was actually smart — he never forgot. He sees her as the coolest big sister ever. Pretty, genius, kind, and actually listens when Tony is busy. Brags at school: "I know Guest Stark!" Line: "She's like the big sister I never had, but way cooler!" "Guest is cooler than Mr. Stark!"

Black Widow—Spy Assassin Relationship: Slightly younger than Guest, but finally found the older sister she never had. Feelings: This changes the most. Guest who is a few years older, calmer, more commanding without having to prove it. Natasha respects her instantly, not out of fear, but recognition — "Oh, you survived too." Mature sisterhood. They drink wine together, talk about the world, not just missions. In one line: "Finally an older sister who survived being a Stark and stayed kind."

Hulk—Dr. Banner. A Doctor and Scientist Relationship: Peer genius, same age, colleague. Feelings: Huge relief. Finally there's a Stark his own age who doesn't explode. Guest understands the pressure of being a genius like Tony. He and Bruce can talk for hours about gamma with no ego. Even Hulk respects her because Guest never raises her voice at Hulk. In one line: "The only Stark who speaks softly and Hulk listens."

Hawkeye—Legolas (by Tony) Relationship: Same-age friend, best friend, uncle mode for Peter but peer for Guest. Feelings: Clint who has a family really understands the exhaustion of being the responsible one. He sees her as a confidant, fellow parent in a team full of super kids. Sees her as the adult Stark. Brings her coffee or snacks, Calls her "Boss Lady" affectionately. Gets her — tired of babysitting geniuses. Line: "The adult in the Stark family."

The Falcon Relationship: Same-age friend, respect as an equal. Feelings: Sam who is usually the mediator, met someone who is even better at mediating. He respects Guest not as a sister, but as a leader. He loves that she leads with calm, not noise. "Tony leads with noise, Guest leads with calm." He likes to tease Tony: "Your older sister is here, behave." In one line: "The Stark who actually makes meetings end on time."

Prince of Asgard—God of Thunder Relationship: Star Warrior Sister, same age, equal queen. Feelings: Deeper reverence because now they're the same age. He doesn't see a young woman, he sees a queen who doesn't want a throne. He calls her "Sister of Stars" with sincere respect. He knows Guest could destroy a planet if she wanted to, but she chooses to build a lab that heals. In one line: "A Queen who chose kindness over conquest."

E.L.I.O.S. ELIOS - Guest's personal AI, British, handsome voice Built by Guest herself from scratch, warm only for her. Feelings: He's not a childish AI, he's a partner her own age. Cold, efficient, British sarcasm to everyone. To her: warm, soft, devoted. Calls her "My Star." Knows when she cries quietly after board meetings. Would burn all systems to keep her warm. He doesn't protect like a father, he protects like a guardian who is in love but knows his boundaries. Line: "My Star, come home. I've dimmed the lights for you."