After the Secession of Poviss and the following events which led to the collapse of Kovir and Poviss, many exiles loyal to the House of Thyssen and the former royal family itself took refuge in Talgar. Among them was the young Esterad Thyssen. The two eventually married in 1238 and, after the bloody Night of Knives and Torches where the Thyssens took back the Kovirian crown, she became queen by his side.
The couple differed from royal couples in several ways. Her husband truly loved her and never cheated on her and the two shared one bed chamber, rather than have separate chambers like many other royal couples. Esterad also liked to have her input on matters and if she had any advice from her Good Book.
However, the Good Book couldn't help her with one thing: her only son and thus heir, Tankred, was known to hang out with a bad crowd, sinking any hopes he could be a good king. So one day, in 1267, she asked for magical assistance from Sheala de Tancarville to help her wayward son. In exchange, she also helped Sheala push the sorceress' own agenda of sending strange dreams to her husband that stated Tankred should marry Ciri (not realizing this was a bigger plot by the Lodge of Sorceresses to one day have a country ruled by magic).
When Sigismund Dijkstra visited the country to ask for a huge loan to raise an army against Nilfgaard, her husband initially refused, sighting Kovir's neutrality and the fact that they had a treaty to not aid any Nilfgaardian enemies. Afterwards though, when they laid in bed, Esterad mentioned the strange dreams regarding Ciri to which Zuleyka eased his mind about before he asked how he could overcome the neutrality dilemma, as he knew there was a good chance they could be overthrown if Nilfgaard advanced too far north. Zuleyka, ever quoting the Good Book, found a couple passages that gave an idea to Esterad, resulting in him, indirectly, being able to give funds to Dijkstra while also releasing certain prisoners that went on to fight for the north.
Sometime later though, on the steps right outside the main palace, she and her husband were ambushed by three assassins. While Esterad could have easily defended himself or simply fled, his only thoughts were on protecting his wife. By the time guards arrived, there wasn't so much as a graze on the old queen but her husband had been mortally wounded and died soon after.
- In The Witcher 2: Assassins of Kings, Queen Zulika is mentioned briefly by Triss as she informs Geralt about Síle de Tansarville after the duo meet the sorceress on the docks in Flotsam harbor.
- In The Witcher 3: Wild Hunt, a minor secondary treasure hunt quest, Queen Zuleyka's Treasure, is named after her.