Blue Horizon has 14 sets of twins and triplets. Here's a list of several who will appear in Book 1~!

(Originally on Tumblr on 03/23/2023.)

at the top right it says 'the triplets.' there's an implied silver crown on chibi frowning raj with silver eyes and his undercut with anime white hair on one side of his head, in a gray shirt and reddish pants and purple boots. it says raj by his legs. there's an implied gold crown on a smiling yet sweating fernando with implied closed golden eyes, his beauty mark, and sweat by his smile, with his usual braid behind a golden yellow shirt and implied violet lungi. his name fernando is by his lungi. a lackadaisically smiling antonio with red eyes is crownless with a little aqua crescent moon clip on his waves-like blue hair. he wears a dark blue panjabi with blood on it and there's blood dripping down his jaw too. his name, antonio, is near his legs.at the top right it says 'the triplets.' there's an implied silver crown on chibi frowning raj with silver eyes and his undercut with anime white hair on one side of his head, in a gray shirt and reddish pants and purple boots. it says raj by his legs. there's an implied gold crown on a smiling yet sweating fernando with implied closed golden eyes, his beauty mark, and sweat by his smile, with his usual braid behind a golden yellow shirt and implied violet lungi. his name fernando is by his lungi. a lackadaisically smiling antonio with red eyes is crownless with a little aqua crescent moon clip on his waves-like blue hair. he wears a dark blue panjabi with blood on it and there's blood dripping down his jaw too. his name, antonio, is near his legs.
raj is on the left, and has long silver hair on one side with an undercut on the other, dark brown skin and browner eye tone, silver irises and a frown on his lips. white suit and violet-blue shirt with pink tie. antonio is in middle with shoulder-length blue hair, red eyes, brown skin and a mysterious smile, wearing a dark blue sleeveless shirt. fernando at the right has dark hair as a long braid, gold eyes, brown skin and a cheerful smile, wearing half-open white shirt. behind the triplets green foliage.raj is on the left, and has long silver hair on one side with an undercut on the other, dark brown skin and browner eye tone, silver irises and a frown on his lips. white suit and violet-blue shirt with pink tie. antonio is in middle with shoulder-length blue hair, red eyes, brown skin and a mysterious smile, wearing a dark blue sleeveless shirt. fernando at the right has dark hair as a long braid, gold eyes, brown skin and a cheerful smile, wearing half-open white shirt. behind the triplets green foliage.

Here's a post with Blue Horizon's book 1 twins + triplets~ ᕕ( ᐛ )ᕗ

🌊 🌙 Antonio, Fernando and Raj Chandrani-Rivera

🌑🌌 Armando and Antonio Herrera-Rivera

☀️☀️ Alejandro [Caldera]-Altaha's binary star

🌀🌀 Yasir and Karim

🪬🪬 Erika and Irina Musa

☀️☀️ Liliana and Lana Caldera

🌑🌑 Antonio Chandrani's cousins Mario + Maria

💧💧 Hazan and Hazal

And about 9 or so characters who are either spoilery or aren't intensively noted in Book 1. 1 is part of triplet OCs I didn't note.

Overall, the amount of Blue Horizon twins and triplets aren't only for the themes/metaphors/cyclical story--when I was 14 to 16 I just decided that in their world they just have more twins than on Earth and thus slowly kept adding twin characters.

Update 07/07/24: I remembered a final pair of twins that made it a likely-total of 15 pairs and trios (unsure but I tried counting) pretty late, but Alejandro has an older brother and sister named Mateo and Julia who are twins. They're the only ones who particularly escape twin-theme naming aside from Yasir and Karim I think and technically Tono, Nando and Raj (hard to not rhyme certain Spanish names), so might as well note them here.

A sketch of a pair of OCs walking down some stairs. A broody-looking Raj staring down at Antonio. Raj has long silver hair, cold silver eyes, a frown, and wears a suit. Antonio has blue hair like waves, aquamarine highlight and streaks, closed eyes, a smile, and is much closer. The background is beige.A sketch of a pair of OCs walking down some stairs. A broody-looking Raj staring down at Antonio. Raj has long silver hair, cold silver eyes, a frown, and wears a suit. Antonio has blue hair like waves, aquamarine highlight and streaks, closed eyes, a smile, and is much closer. The background is beige.
On the left in lavender is Antonio who is looking back irritably with a visible red eye, a frown and furrowed brow. He's without a shirt, and holding fuchsia threads doing some sort of cat's cradle, as well as wearing an aquamarine-and-blue lungi. On the right in pink is golden-eyed [implied thru the egg yellow] Fernando who is looking back with a long braid and easy smile, holding a fuchsia rose. He's wearing a form-fitting tanktop and a lavender belt and light violet-looking pants.On the left in lavender is Antonio who is looking back irritably with a visible red eye, a frown and furrowed brow. He's without a shirt, and holding fuchsia threads doing some sort of cat's cradle, as well as wearing an aquamarine-and-blue lungi. On the right in pink is golden-eyed [implied thru the egg yellow] Fernando who is looking back with a long braid and easy smile, holding a fuchsia rose. He's wearing a form-fitting tanktop and a lavender belt and light violet-looking pants.