”Requires? Vin thought. She already didn't like that tone, and she had little desire to meet with Elend's former betrothed. But House Elariel was one of the most powerful Great Houses--she was probably not someone to dismiss offhandedly.— Vin, thinking of Shan Elariel
Members include Shan Elariel, a Mistborn from Luthadel. Shan was once engaged to Elend Venture. House Elariel also had the services of at least one other Mistborn, who may or may not have been a member of the family.
Elariel seems to be a house well accustomed to intrigue. Its ballroom, full of secret alcoves and muted lighting, seems perfect for discussing secret alliances and schemes while at balls. Once Elend discovers that Shan Elariel is a Mistborn, he suspects that House Elariel's intention was to have him killed as soon as an Elariel grandson was born. This plot, if true, is an example of a strategy a House like Elariel might use when confronted with a dominant, apparently unassailable, force like Venture, and demonstrates a tendency towards patience and subterfuge.
It could be that House Elariel has done this sort of thing before. Multiple times in later books, Vin refers to certain Houses being "cousins" of House Elariel (including Patresen, Habren, and Seeris). This could indicate that Elariel was once part of a larger family that split apart, that Elariel often recruits allies through marriage, or some combination of the two.
On the night the Lord Ruler was killed, House Elariel was the second most powerful house in the city. Because Straff Venture fled the city, and Elend defected to the rebellion, it could be argued that when Elariel was defeated by the skaa rebellion, it had become the most powerful remaining Great House, a notable achievement.
It is unknown if any Elariels survived the fall of the Final Empire, or if any survivors made it through the subsequent wars or the string of natural disasters caused by Ruin. Unlike House Tekiel, House Elariel has not been mentioned in the Mistborn Era 2 novels. According to Brandon, the survivors of House Elariel ended up "All over, really". 
Keep Elariel is smaller than Keep Venture, but it has a separate party ballroom, which is the only part of the Keep that Vin observes. The ballroom building is squat, and is one of several lower wings extending from the main keep. Guests are required to climb steps in order to enter the ballroom. The ballroom is only a single story high, and all of the stained glass windows are in the ceiling. The circular rose-window skylights shine from above, lit by small lime-lights on the roof. Each table is set with candles, and despite the light from above, there is a reserved darkness around the room. To Vin, it seems private, despite the numerous people attending the ball. The room is obviously designed to accommodate parties. A sunken dancing floor lies at the center of the ballroom, where the lighting is better. There are two tiers of tables circling the dance floor: the first tier is only a few feet above, while the other is farther back and about twice as high. The deep crystalline colors from above project patterns across tables and people, creating an impressive atmosphere, yet making it difficult to distinguish faces.
|Mistborn Era 1|
The Final Empire · The Well of Ascension · The Hero of Ages
|Characters||Vin · Kelsier · Sazed · Elend Venture · Marsh · Spook · Breeze · Ham · Clubs · Dockson · Straff Venture · Zane · Ashweather Cett · Tindwyl · Allrianne Cett · TenSoon · Yomen · Quellion · The Lord Ruler · Alendi · Kwaan|
|Places||Final Empire · The Dominances · Luthadel · Kredik Shaw · Pits of Hathsin · Kandra Homeland · Urteau · Fadrex City · Tathingdwen|
|Ethnicities and Species||Skaa · Nobles · Terrismen · Inquisitors · Koloss · Kandra · Mistwraiths · Southern Scadrians|
|Organizations||Skaa rebellion · Steel Ministry · Keepers (the Synod) · Worldbringers|
|Mythology||The Deepness · Terris Prophecies · Well of Ascension|
|Era 1 books||Mistborn: The Final Empire · The Well of Ascension · The Hero of Ages · (Mistborn: Secret History · The Eleventh Metal)|
|Era 2 books||The Alloy of Law · Shadows of Self · The Bands of Mourning · The Lost Metal · (Allomancer Jak and the Pits of Eltania)|
|Shards||Preservation · Ruin · Harmony|
|History||Classical Scadrial · Final Empire · Catacendre · Elendel · Southern Scadrian|
|Magic||Metallic Arts (Allomancy, Feruchemy, Hemalurgy) · Metalborn · Mistborn · Misting · Savant · Ferring · Twinborn · Compounding · Atium · Lerasium · Ettmetal|
|Other Media||Mistborn Adventure Game · Mistborn: Birthright · Mistborn film · Mistborn: House War|