He was later at the Enclave meeting to discuss the incidents that had happened around the city. While waiting for the Consul to arrive, he amused himself by tossing shiny, valuable, breakable objects near the fountain in the Sanctuary.
He was then brought to his cousin James's engagement party. He was left with his cousin Thomas while his parents helped set up. When Thomas tried to pawn him off on Lucie, he began demanding Matthew and Oscar.
In December 1903, he attended James and Cordelia's wedding ceremony. Despite the loud noises of celebration, he remarkably slept through the ceremony in the nursery and into part of the reception in his mother's arms. He later woke and was seen playing with his cousin Eugenia and Ariadne Bridgestock.
When Leviathan attacked, his mother rushed to his room to be by his side and provided light for those in battle. After the attack ceased, Cecily to him to visit Gabriel in the infirmary—as he had been injured during the fight—and they stayed the night with him at the Institute. During dinner, he played with Lucie, who allowed him to walk on the table and occasionally fed him biscuits.
- Clockwork Princess (alluded to)
- Every Exquisite Thing (first appearance)
- Chain of Gold
- Chain of Iron
- According to a found family tree, Alexander died in 1971 at the age of 70 or 71.
- One of his brother Christopher's descendants, Alec Lightwood, shares the same name as him.