The Siren and the Chimera (with @Dances_with_Shadows)

(Well, they are a protective bunch to begin with. And then Lance taking a legitimate interest in her because she's someone he can get along with sets off a chain reaction, making the other two brothers want to keep her safe for Lance's sake and because they share a similar interest due to sharing a soul. But their interest isn't romantic. Especially for Levi.)

The two other brothers headed out as well to grab a bite of lunch, though they avoided the cafe Tempest went in and instead headed to a KFC, starved of meat thanks to their vegetarian brother. They got a bucket each and chowed down, uncaring of the people staring. They were hungry males. Leave them alone.
Leon swallowed the piece of the thigh he was chewing. "So… Lance still stuck?"
"Yeah," Levi replied nonchalantly.
"Whhyyyyyy?"
"Because he pissed me off."
"Ah. Has to do with that girl, right?" Leon shook his head sadly. "I love him, but the dude needs to get out more. He's like from the stone age, no idea how people work. Too bad he's a goat and not a bird. Then I could call him Bird Brain."

(Introducing another mythological sibling group. Take a guess at what creature it is. Hint: It's a sibling of the Chimera)
Five women entered the cafe, all ten eyes seeming to search for something. Or someone. Who knew besides the five of them? They all looked alike except their eyes, with silky black hair and slim but sharp features.
The one with gray eyes was named Herais. The one with sky blue eyes was named Yanna. The one with earth green eyes was named Doris. The one with cool brown eyes was named Roxane. The one with kaleidoscope hazel eyes was named Alexis. Their eyes all simultaneously landed on Tempest. They didn't look threatening, but they definitely didn't give off friendly vibes.

(yes)
The one with brown eyes whispered to her sisters and approached the two. "Hello. I'm Roxane." She had a prominent Greek accent. "I wish to speak with the one known as Tempest." She blinked and tilted her head slightly, like a dog discovering something new.

"Nonsense." She waved a dismissive hand. "You smell like a siren, and my brothers were quite clear of your looks. You are Tempest, yes?"

The five sisters exchanged a look. They spoke quietly in Greek.
Heratis: "I told you! Everything involving those two is just trouble."
Doris: "But they seemed genuinely concerned for her safety."
Yanna: "I'm with Doris. Levi wouldn't be one to fall for her charms. If he's concerned about this war and her, then it is worth investigating."
Roxane: "Oh, Leon likely guilt-tripped him into saying that. You know how he is."
Alexis: "But war is coming. As creatures of destruction ourselves, we will be employed by the gods, whether it be for the attackers or the defenders."
Yanna: "The Chimera has a point, and so does Alexis. Perhaps we should get involved before we are called. Work alongside the demigods to protect this world."
Doris: "See? Some of us could watch over this Tempest for them while the others investigate the other gods. See where they stand in this war."
Alexis: "Maybe convince them to back up Earth?"
Heratis: Sigh. "It's worth a shot, at the very least. Alexis, go to the Lion and the Dragon and inform them of this. Yanna, Doris, follow the girl and keep a close eye on her. Alex, you join them when you are done. The rest of us will pay a visit to the gods."
The sisters all nodded in agreement, then exited the cafe and headed in their respective directions.

Leon and Levi were still eating their KFC when Alexis showed up. "We found her, and then she ran away with a child of Aries. I believe she wants nothing to do with you lot." She then proceeded to explain the Hydra's plans regarding the war.
The two brothers thanked her, and she vanished to join Yanna and Doris, who had already picked up the two scents. Levi looked at Leon before he could say anything. "No. We're not calling anybody else."
"But I like her! And I wanna go to war!" he whined.
Levi sighed. "We're still going to war."
"But not with her."
"You're being a child. You know that, right?"
"Very much so."
Levi shook his head. "Just leave her be. Alexis is right. Just drop it and let's get on with our lives."
Leon pouted and sadly poked at his chicken. "Fine."

The three hydra sisters watched in silence, simply keeping an eye on Tempest as instructed.

Lance finally got his horn free.
It wasn't fun.
He had to kick the tree down.
Now in his human form, he grumbled Greek profanities directed towards his still absent brothers and threw himself on the bed of his and Tempest's hotel room. Or perhaps his, if the lack of her stuff was any indication. Levi was royally pissed at him for some reason regarding Tempest. It was strange.
Why was he suddenly only thinking about the girl?
It wasn't her charm. He was immune as an ancient Greek monster and son of Echidna and Typhoon. So what was it?

The three hydra sisters exchanged a look, now paying closer attention to the demigod gathering. So she did want the brothers there. Was there more to the story?

The sisters played rock-paper-scissors to see who would deliver the message to their brothers, but the thing about sharing a soul–they all did the same thing.

Levi and Leon had finished their KFC and were now strolling through the city, window shopping. Levi wanted a new pair of headphones and some new video games. Leon wanted to check out the hunting supplies and try his hand at bow hunting.
Lance was still lying on the bed, frowning at the ceiling as he tried figuring out what he did wrong.

Levi had gotten his headphones, and he was using them to ignore his annoying brother. Leon was going on and on and on about hunting and how cool bow hunting would be and that he would try it out when they went back to the hotel—and some other random topics. Generally running his mouth just because.
A few female passersby eyed Leon, giggling when he winked at her with a smirk. Levi just rolled his eyes and buried his nose in his phone as he tried out some really base-y songs with the headphones.

Levi noticed him first, eyes lingering just a little too long to be considered casual.
Then Leon noticed what had caught his brother's attention and elbowed him in the side. "You're drooling."
Levi shot him a glare. "Am not." He huffed and kept walking, avoiding eye contact with the guy.
Leon snickered and approached Aquarius. "Yo."

Levi's face turned red as he heard the nickname and literally turned into a tiny, fire red lizard right then and there, scurrying away as fast as he could.
Leon laughed at his brother's reaction, choosing to ignore his nickname. "Yeah, I'm the Lion." He jerked his chin. "Who's asking?"

"That Tempest girl?" He shrugged nonchalantly. "She send you to deliver her final 'eff off'?"

Leon shoved him off. "Lay off dude! I've barely even talked to her."

"How the hell am I supposed to know?! All I know is that some shit happened with the gods, Lance had us take her to a hotel, something happened between them about the war, and then we're suddenly not allowed to see her. Levi's pissed at Lance, if that helps." Leon seriously had no idea what was up with Tempest. It seemed Levi was the only one who had an idea of what was going on.