I really like Orwen's story, and I thought i would share my research regarding her early childhood ;)

Orwen is the daugher of the Immortal Alchemist, (a Luthraghon) and a human mother from Iliya Island. She was a small baby when Caphras, her father left the island. Soon her mother passed away, taken by the Black Death. She was reared by her grandmother, Diega. As a child Orwen was bullied by others, because of her elven appereance. One day, Diega took her to Kamasylvia, and gave her the only book Caphras wrote in the human language, his journal.

In Kamasylvia, she was placed in the hands of a Vedir, Opencilla, who became her nanny. Although the Ganelles rejected her, because of her mixed heritage, two people still cared about her, her nanny, and Princess Catherine.

Catherine was the third princess of the Ganelles, daughter of Oriana Ornette. The young pincess wanted to restore the Kamsylve's light. But to revive the divine tree, she needed to gather the songs of the tree oldest spirit of Kamasylvia. Her quest was impossible, because Narc (one of the ancient spirits) left Kamsylvia, with the Ahib.

Fortunately one of the other spirits, Antis, revealed how Catherine could replace the third song. She had to find the Purest Soul's Light, that seeped out of the Root Realm, and had to drench the Field Of Yinaros with it.

The Spirit Antis directed Catherine to Orwen, whose name means "the key" in the ancient language of the spirits. (Also Caphras came from the Root Realm)

Catherine tried to gain Orwen's trusth, but it was very difficult, at first, because the little half-elf was very withdrawn, and mistrustful. But the princess was relentless, and after a time, her kindness melted the ice of Orwen's hearth, and they become best friends. Catherine's affection became sincere. 

The princess decided to abort her plan, because she didn't want to sacrifice Orwen, but rumors got out, and everyone found out that the half elf was the key, beside Orwen. Fearing the Ahib, or Amelia (queen of Kamasylvia at that time) would hunt the daughter of Caphras down for her blood, Catherine banished Orwen from Kamsylvia. Opencilla gave Orwen to priestess Herawen, who took her out of Kamsylvia. The same day, princess Catherine was assasinated by the Ahib, and Opencilla was punished by queen Amelia, who found out Orwen left the elven homeland. Opencilla kept Caphras' journal, and joined the Ahib. 

Little Orwen was heathbroken, because she didn't know why her best friend turned against her, and kicked her out of Kamasylvia.

As a source, I used the Kamsylvia main questline, the Orwen, Opencilla knowledge entry

You should play through the Odyllita questline too. It sheds some additional light to Catherine's death (and a lot of other Kamasylvia lore too) ;)

I actually made a 3 part lore post of Orwen's life on reddit, tho I only shared her childhood here. ;) (Since it didn't really affected Orwen who killed Catherine, I thought I wouldn't spoil the story... ;P )