It could be a good ending, a closure of the story that satisfies the character and the readers alike. A well-deserved rest, maybe even a new life of retirement and joy. To know that everything worked fine.
But, this is CoC, it's a universe where things go south (and we love how they do!) and the game is full of options for Bad Endings - so it should end with one of those options. They sure have variety!
Maybe it could have an Open Ending? CoC has a lot of big quest and I barely dedicated the comic to the main one... Maybe it should left the door open, face the Witches, the Minotaurs, go back to find a corrupted Marae...
Or maybe a part of you don't want it to end. Maybe it should just end in a gigantic Cliffhanger! Martin's life of adventure will continue even if we dont know much more about it this way. Who knows? That cliffhanger might become a short comic some day.
Or maybe you want something more. Something more surprising? You want things to go more outside of the box, something Unexpected. It's not happy, not sad, just something that maybe you didn't see coming but deep inside you knew it could or would happen.