Commander Miniana is a miniature version of Commander Zilyana that can be unlocked as a pet from an Auburn lock, which is obtained as a drop from killing Commander Zilyana. The odds of receiving the item are 1 in 5000 (normal mode), or 1 in 1000 (hard mode), both with a threshold of 1000 (explanation of drop mechanics). After the item is used, Commander Miniana can be summoned from the pets tab in the Customisations interface.
This article on a pet has an associated dialogue page. Click here for a transcript of possible conversations with this pet.
Conversation 1 is a reference to players casting Blood Barrage on Zilyana and her minions to stay in the room for prolonged periods of time.