Some Mahanon Lavellan headcanons I wrote a few days ago: (This is for my Inquisitor! Yours can be completely different!)
Mahanon wanted nothing more than to be proposed to by Dorian. In fact, he expected it during Trespasser when they all gathered in Val Royeaux. Imagine his surprise when he learned Dorian was leaving for Tevinter and would not be returning anytime soon.
Elrogathe and Mahanon always liked to have little competitions from time to time. While Elrogathe was strong with swords and could barrel through trees, Mahanon was swift and hard to catch. But it would end in a tie.
At one point, Mahanon had a small crush on Elrogathe but it quietly faded as they remained friends. After realizing his sexuality, Mahanon never pursued in his clan. Instead, he would submit himself to his studies as the Keeper's First and any affection he felt, he kept to himself. It was only once he met Dorian, someone he could openly flirt with, did he begin to unwind.
After the events of Tresspasser, the first thing on Mahanon’s mind is checking the well being of his clan. He will insist he go visit them. He doesn’t bring anyone along.
You only get stories out of him if you give one yourself. He loves to hear about people's lives but isnt too keen on sharing his own. So, you have to give him something in return.
He endlessly goes over the events of Ameridan. His story deeply disturbed him. It came to the point that he made sure Josephine included details of his race in every text and letter that included his name. He would not be known as a human; he would be known as Mahanon Lavellan. The Dalish elf who reunited Thedas.
When visiting the Emerald Graves, he actually broke off from the group to go exploring. This little adventure was a bit depressing however, from the graves of all the fallen Dalish warriors and finding journal entries of those who perished.
He loves to trace his hands over Dorian when they cuddle. He records every line, every shape, and the touch of his skin secretly so that if they should ever part, he'll remember.
During his days of living at Clan Lavellan, Mahanon's nose was always buried in a book about magic. He needed to learn as the Keeper's First so that one day, he will lead the clan and protect them.
Kore actually kissed Mahanon once. It was at night when the two of them were guarding a forest opening, keeping out for wolves. They had discussed what the future held for the both of them and Kore confessed she had strong feelings for him. But Mahanon smiled, brushed her hair back with his thumb, and declined her advances.
Mahanon didn't know he was gay until one day someone asked if he were to bond with anyone. He said he had no interest in any of the women here. The clan member had laughed and said "Maybe you dont like women." He agreed.
His favorite stories growing up were the ones of the twins: Dirthamen and Falon’Din. He would insist his parents retell him the stories every night before he fell asleep. He keeps those memories close.
His mother died from contracting the werewolf disease during the Fifth Blight. His father, Mineras Lavellan, fell into a pit of grief; one that was hard to climb out of. Mahanon swore that he would never leave his father side until the days of mourning past. He was 24 during the time of the Fifth Blight.
He has three younger siblings; two boys and a girl. He spoiled them rotten.