Disclaimer: I do not own Arrow, Supergirl or anything else you may recognize

Wanted to write a fic with this pairing for some time, and I'm finally writing one. Hope everyone enjoys.

Lena was working on her computer when she heard the sound of particles shifting behind her and turned around to see Rhea on her balcony.

Getting up, she glared. "I thought I made myself clear. Our business is done. Now get out of my office before I call security."

"I'm sorry for what I did", Rhea said. "You were right, I lied to you. I pretended to be of this world when I'm not. But I only did that because I know how much your mother hates aliens. I presumed you'd be the same."

"That's what most people do when they hear I'm a Luthor. They presume", Lena said, her face turning into a snarl as she said the last word.

"Everything else I told you was the truth", Rhea assured. "Being betrayed by your own blood. There is nothing more painful. I know you understand that."

"What do you want from me?" Lena asked.

"I want exactly what I proposed", Rhea said as she stepped inside. "I want us to work together to create a transmatter portal."

"Portal, interesting word", Lena said as her face turned into a smirk while she started pacing around, the uncertainty and feeling of betrayal gone, confusing Rhea. "You see, there's a popular movie here called 'The Avengers', which solidified a very popular franchise. Humans were tricked into opening a portal in that movie by a God. And an alien army arrived from the other side to destroy them."

"So you are like your mother after all", Rhea said, her voice laced with disappointment.

"No, my mother has a prejudice. I only turn against someone after I have full facts", Lena said, glaring into Rhea's eyes. "Otherwise, I'd just make myself look stupid, which I don't want to. My husband taught me that."

Rhea tried to absorb what Lena was saying as she said. "I know who you are. You are Rhea, Queen of the Daxams."

Rhea's eyes widened in horror as Lena said. "You see, my husband knows your son very well, and he knows the phrases you use, so once you said "To the Gods", I just needed to put two and two together."

"How does your husband know so much?" Rhea asked, only to hear a bowstring being pulled.

The two women turned to see Oliver Queen, dressed as the Green Arrow, aiming an arrow at Rhea.

"Rhea, you have failed this city", Oliver snarled at her.

"Oh, so it is you", Rhea said, her confidence returning. "The human ally of the heroes."

Looking at Lena, she said. "Who would have thought your stupid looking husband was the vigilante who strikes fear into the hearts of criminals?"

"No one, which is why the look of surprise on your face is oh so satisfying", Lena smirked.

"It is good to see a husband and wife actually trusting each other", Rhea said, her tone now sad. "If only my husband supported me."

"What did you do?" Oliver growled.

"I killed him when he refused to attack Earth for me", Rhea stated, making the other two glare at her.

"You're a bigger monster than I thought", Lena said to Rhea.

"How are you going to kill me?" Rhea asked Oliver. "You are nothing but a dot when compared to Supergirl and Flash, and they have failed to take me down so far."

"Yes, but I make do with what I have", Oliver quipped before he fired at her.

Rhea easily grabbed the arrow and smirked at Oliver, only for the arrow to release some kind of toxin on her, making her cough and choke violently as she fell to the ground, coughing her lungs out.

Oliver and Lena stood over her as the former said. "Its lead, you know, your biggest weakness. Like I said, I made do with what I have."

And with that, Rhea breathed her last and disintegrated into nothingness.

Lena looked at Oliver as the two smiled at each other.

"Good thing you told me about a strange woman who came to you with a proposal for a transmatter portal", Oliver said as he removed his hood and mask, revealing his handsome but still haunted face.

"Such things never sound good, especially when coming from people you don't really know", Lena said. "Thank you for trusting me with this, Oliver Queen."

"I trust you with my life, Lena Luthor-Queen", Oliver said with a smile as the two kissed each other passionately on the lips.

Later

Oliver and Lena returned home after having informed Kara and Mon-El of what had transpired. Mon-El had been furious at first until Oliver had told him his mother had murdered his father, after which he had seemed to accept his mother was too far gone.

Kara didn't really approve of killing, as always, but Oliver and Lena knew that sometimes, you needed to get your hands dirty so others could live in peace.

"Life has gotten much more complicated and crazy if you think about it", Lena said. "I mean, if we hadn't planned this out, we would be in a real-life Avengers movie, except during the unpleasant bits."

"Which we do not want, especially after the Dominators", Oliver said and she nodded. "Or Adrian."

His eyes seemed to look haunted as he said that name, and Lena held his face. "Hey, look at me."

Oliver looked at her as she said. "He is gone. Do not let him get into your head again. He was the monster, not you. You are a good man who knows when to make the tough calls."

"Thank you", Oliver said with a smile as he lowered his head and then lifted it, looking at her with emotion in his eyes. "I just wish people think the same way about you one day."

"Well, it is hard to get rid of the surname", Lena said as she brushed her hair.

"I know the feeling", Oliver said. "After my mother's role in the Undertaking was revealed, people hated me for my surname too."

"Remember their reactions when they heard we were merging?" Lena reminded and Oliver groaned. "'The Demon Queen Spawn and The Scorned Luthor Daughter join forces.'"

"It wasn't smart, it was cheesy", Oliver said as the two chuckled.

"I know", Lena said as the two held hands. "But you were the first one to treat me like a normal person, not a Luthor. You helped me get over my mom's death. Thank you for that."

"Like I told you once, you never have to thank me for that", Oliver assured as he cupped her face. "I love you, Lena."

"I love you too, Oliver", Lena said as the two kissed each other, with Lena taking off his shirt. Oliver took off Lena's shirt and helped her unstrap her bra before carrying her to the bed, with her moaning as he began kissing her chest.

And that's the end of it.

So as the one-shot explained, Supergirl exists on the same Earth as Arrow and Flash, and the three team up much more often, which is realistic, unlike in the shows.

And yes, Oliver and Lena merged their companies during Season 2 of Arrow, and due to their similarities, got together, and are now married.

And Rhea (who doesn't know the identity of Oliver) failed in her plans.

I didn't do the best job with this, but I just needed to write something for this pairing, I just felt a strong urge for some reason. Hope to see more stories with this pairing some time in the future.

Still hope it was enjoyable to read.

Hope everyone and see you all next time with another update. Until then, stay safe from the coronavirus ya all!