Oh No! My Little Sister Fell for Someone Else's Brother

[Japanese-style Western fantasy, ensemble cast, multiple pairings (siscon warning), slow-burn journey]

Nai An never imagined that one day Nai La, his beloved younger sister, who had been by his side for more than a decade, would suddenly tell him she wanted to travel with an elf whose background was unknown.

To protect his sister and make the man back off, he decides to join their adventure. But before long, his attention begins to drift toward the elf girl traveling with them...