Hawke had arrived with Isabela only ten minutes later but it was already too late. As soon as he saw Fenris still in Anders arms, he collapsed and screamed in anger and in grief. He had once again failed to save the important people in his life. Isabela put a hand on his shoulder but she herself had tears in her eyes.
In the months after Fenris' death, their group had started to fall apart.
Anders gave himself fully to his cause, barely eating or sleeping. When anyone in the group tried to talk to him, he turned them away instantly. They all knew Justice was planning something big but they were powerless to stop him.
Hawke had buried himself away in his mansion, rarely ever coming out. He had blamed himself for Fenris' death and even after everyone's best try, there was no convincing him otherwise. He avoided Anders completely; he knew the mage blamed him. He had sworn to get there before sunrise and according to Anders, Fenris had actually held on until then, waiting.
Isabela had returned to her usual self for the most part. If you knew her well enough though you could tell she was just covering her true feelings. She had approached Hawke once and told him she had found a boat and planned on leaving Kirkwall soon. He did not try to stop her.
Merrill, distressed about Hawke, spent most of her days in the company of Isabela or Varric. She still lived with Hawke, and had tried many times to comfort him, but his guilt was too great.
Once news came to Kirkwall Sebastian spent even more time in the chantry. Of their group, Sebastian had the closest friendship with Fenris and was devastated to hear of his passing. He prayed for him daily.
Varric started spending more nights alone at the Hanged Man then was comfortable. He tried his best to help people move on but the elf had apparently played a bigger role in their group dynamic then any of them had thought. He had also arranged the funeral for Fenris, at the request from Anders.
Aveline was saddened when she heard the news but turned her attention to Hawke. She was determined to not let him wallow in self-pity, and after many attempts and fights she started to get him outside again. If only to go on short missions and vent his frustrations by brutally killing anyone he was thrown at.
Eventually the letter from Varania came, and was an obvious trap. Anders had sought out Hawke for the first time since Sundermount and asked him to come with him. Fueled by their anger they easily decimated Danarius' army. Anders got the pleasure of crushing the magisters skull into the floor himself. When Hawke asked why Justice hadn't interfered at all, Anders simply answered, "This was my vengeance, not his." And left the Hanged Man.
When Anders started his revolution by blowing up the Chantry, Hawke sided with the mages… And gave them a martyr.