Dryya

Drya is one of the Pale King's Great Knights chosen to protect Hallownest. She was presumably the chief protector of the Queen's Gardens. Her corpse can be found outside the structure where the White Lady lives, which heavily implies she died fighting against the Traitor Mantis to protect her.

Trivia

 * In a kickstarter update, Drya was meant to be a boss.
 * Drya could have died protecting the White Lady, the corpses of the Mantises supports this.