The Lovely, The Handmaiden, The Starlit One
Ilmarë was a Maia known as the handmaiden of Varda and was one of the chiefs of the Maiar. This is about all the information we get about her from the Silmarillion.
In Tolkien’s earlier works, she was at one point called Erinti and was associated with love, beauty, and music. Here she was the sister of Salmar/Noldorin and Omar/Amillo, who were both also associated with music. The three siblings were notable in that they were the only Valar (the concept of the Maiar hadn’t been developed yet) to leave Aman and live among the elves on the island of Tol Eressëa.
Tolkien later changed her to be the daughter of Varda and Manwë and the sister of Eönwë. Here they were called the eldest of the children of the Valar, since at this point Tolkien still hadn’t created the Maiar. She lived high in the sky and is hinted to be powerful, but is also described as being uninterested in war.
Once Tolkien developed the Maiar he abandoned the idea of the Valar having children, resulting in the Valar becoming more like angels and saints and less like Greco-Roman or Norse deities. Ilmarë became a Maia of Varda and her brother Eönwë became the herald of Manwë, and they are described as “chiefs” of the Maiar. She therefore retains her power and association with Varda, but she is no longer described as lovely and beautiful like in earlier texts. Of her earlier “brothers” Salmar becomes a Maia of Ulmo who made his conch shell horns, while Omar/Amillo was dropped.
As a beautiful and lovely maiden who is associated with both the heavens and the sea (Erinti lived on an island and her “brother” Salmar is associated with the sea) Ilmarë can perhaps be seen as an angelic, idealized version of the love goddess Venus/Aphrodite. It is generally agreed that Aphrodite’s cult originated from eastern cults of goddesses such as Isis, Ishtar, Astarte, Asherah, and Atargatis, who all had associations with love as well as stars and the sea. Her name also heavily implies a connection to Ilmatar, a virgin spirit of the air in Finnish mythology who is impregnated by the sea; Tolkien drew heavily from Finnish mythology in his works. Ilmarë’s depiction as a powerful, heavenly woman who has no interest in war also indicates that, like many of Tolkien’s female supernatural characters, she is influenced by the Virgin Mary via Tolkien’s Catholic faith.