According to the Chinese, Japanese, and Korean pronouns used by the twins Aether and Lumine to address each other in the opening cutscene and in later interactions, Aether is referred to as the older twin, while Lumine is addressed as the younger sibling.
These pronouns are significant in East Asian cultures as they reflect the hierarchical relationship between siblings. In Chinese, for example, the pronoun “gege” is used to address an older brother, while “didie” is used for a younger brother. Similarly, in Japanese, “oniisan” is used for an older brother, and “otouto” is used for a younger brother. Korean follows a similar pattern with “hyung” for an older brother and “dongsaeng” for a younger brother.
In the opening cutscene of Genshin Impact, Aether is seen protecting Lumine from an unknown force, which further supports the notion that Aether is the older sibling. Additionally, throughout the game, Aether often takes on a more responsible and protective role towards Lumine.
It is worth noting that the exact ages of the twins are not explicitly mentioned in the game, so we can only assume their relative ages based on the pronouns they use and their interactions. The focus of Genshin Impact is more on the twins’ journey and the events unfolding in the world of Teyvat rather than their specific ages.
Based on the pronouns used by the twins Aether and Lumine and their interactions in Genshin Impact, Aether is portrayed as the older sibling, while Lumine is depicted as the younger twin.