Grandmother

Her first appearance onstage
Name:	Terebithia
Age:	Unknown, but possibly in her late 60's.
Occupation:	Knights of Jove cabal leader, Dowager Princess of Sturmhalten
Residence:	Paris, among other places
Debut:	Gently educating Seffie ✣ on deviousness. (She is mentioned for the first time much earlier. ✣ )
Relations
Children:	Aaronev Wilhelm Sturmvoraus
Relatives:	Tarvek, Tweedle, Seffie (grandchildren); Violetta
Marital Status:	Widowed

Grandmother (also Grandma, Grandmama) of would-be Storm Kings, properly named Princess Terebithia. She rides herd on Houses Sturmvoraus and von Blitzengaard (not to mention the Storm King Conspiracy) and is also the superior of the whole order of the Smoke Knights, or at least Violetta's branch of that organization.

Grandmother's Name and Fame

When the story moves to Paris, we discover that Grandmother's royal title is the Dowager Princess of Sturmhalten. She apparently makes the major decisions for Houses Sturmvoraus and von Blitzengaard or at least the ones that stick, especially now that, post-Timeskip, she is reported to have lost her husband ✣ and has become/taken over the duties of the Council.

When her relatives speak of her, they refer to her as "Grandmother," "Grandmama," or "Grandma," often in tones of fear and respect. Her grandchildren treat her with more familiarity and even affection, but respect and fear are not entirely absent. In Paris, she is referred to as Highness by her servants and Princess ✣ by Mister Obsidian. It finally takes the Master of Paris himself to reveal ✣ that her first name is Terebithia.

The Master and Grandmother treat each other as old and mutually dangerous rivals for influence who have nevertheless developed a mutual respect and even a certain backhanded fondness for each other.

Her ability to throw a party has also achieved a degree of infamy; it is her party sleigh ✣ that Agatha commandeers for her escape from The Refuge of Storms. Her party to welcome Tweedle to Paris (described in more detail below) seems destined to become the most notorious in Parisian history, since it (and the associated events) shake the city to its very foundations.

Grandmother and Lucrezia

According ✣ to Violetta at least, Grandmother hates Lucrezia, and has ordered all of her followers to break off contact with the latter woman and her forces. Smoke Knight cells still loyal to Lucrezia, like one led by Madwa Korel, have been purged from the cabal, and all other factions' smoke knights have standing orders from Grandmother to set aside rivalries and cross agendas to pursue the rogue cells for elimination should they be encountered.

Grandmother In Paris

After hearing several passing mentions of her, the reader finally meets Grandmother ✣ in person in Paris talking to Seffie as Agatha and Tweedle's arrival sends social (and eventually physical) shockwaves through the city. Her love of parties immediately comes to the fore as Seffie recieves a message from Colette Voltaire, stating that her father has "suggested" she and Seffie change a party already in the planning stages to into a masked ball. Grandmother acknowledges that they can hardly refuse a request from the Master of Paris and so the change is made. One of the participants at this affair is a disguised Tarvek; Grandmother sends a team of Smoke Knights led by Mr. Obsidian to ruthlessly retrieve him from the forces of the Immortal Library. Their meeting ✣ after this is surprisingly cordial, all things considered.

The party goes forward ✣ , around a theme of honoring Tweedle's (still somewhat theoretical) ascension to the Storm King's Lightning Throne, with a series of unexpected guests arriving that truly elevate it to the event of the season, if not the decade: The Queen of the Dawn, the notoriously party-averse Simon Voltaire, Agatha and her team, a swarm of rampaging Geisters, and finally the original Storm King himself, Andronicus Valois, released from his temporal prison under Paris. Voltaire deals with the Geisters, but it takes the combined efforts of nearly everyone present to put down the now-raging undead Valois. He finally crumbles to dust, Tweedle literally claims his crown, and to celebrate Grandmother unleashes ✣ Captain Wrenkula, a Spark in her employ who specializes in creating very public and explosive spectacles, sending a glowing parade marching through the city's darkened streets.

As this goes on, Grandmother compliments ✣ The Queen of the Dawn/Zola on her nearly successful takeover of Paris, and announces her intention to keep Zola from being caught by Colette, but what she intends to do with/for/to the Queen in the long run remains unstated; to date this conversation is the last time we've seen either woman in person. Mr. Obsidian is also seen ✣ reconnecting with Tarvek, and the latter man then disappears from Paris as well; it's easy to infer that Grandmother ordered his re-kidnapping, but we later learn that it was Seffie, in order to covertly send him after Agatha to England. Grandmother in turn (reportedly) dispatches more Smoke Knights to retrieve him, leading to a mid-Channel multi-sided fight aboard the airship carrying Tarvek. Grandmother's forces are mostly killed, with a couple of survivors fleeing the scene with Tweedle-minion Jaron as a prisoner.

Even after all this, it should be noted that it is still not at all clear what Grandmother's ultimate goals are, nor do we know who she'd genuinely like to see become the new Storm King: Tweedle, Tarvek, or None of the Above.

Grandmother's Current Whereabouts

Dispatched back to the continent by Queen Albia to combat a Polar Ice Lord invasion, Gil gets a report ✣ from Tarvek and Seffie: following a bloody forced entry of her supposed current domicile in Paris by some of their family's Smoke Knights, Grandmother now appears to be among the missing. Unsurprisingly, there is no mention of Zola.

Possibly Relevant Information

Grandmother's given name is presumably a homage to the 1977 children's novel Bridge to Terabithia by Katherine Paterson and/or the book's 2007 film adaptation. (Note alternate spelling.)