Given my lack of knowledge about Atish Fishan's Urdu novels, it's challenging to define the main themes. Generally in Urdu literature, themes such as the struggle for identity, the importance of morality, and the power of emotions are prevalent, and there's a possibility that his novels also incorporate these in some way.
It's hard to say. You might need to do some research or look for reviews and comments from people who are familiar with it to find out if it's based on a novel.
Unfortunately, without more in - depth knowledge of Atish Fishan's Urdu novels, it's hard to recommend his works directly. However, you could look for reviews and discussions on Urdu literature platforms which might lead you to his notable novels.
I'm not sure exactly what the ending of 'ishq mein marjawan' is as I haven't watched it fully. But generally, in such shows, it could end with the main couple getting married and living happily ever after. Maybe they overcome all the obstacles like family differences or some villain's plots.
I'm not entirely sure as I haven't specifically read or known the exact 'ru baru ishq tha' story. It could be a story with a happy ending where the characters finally get together and their love triumphs over all the obstacles.
I haven't had the chance to read 'ishq e aatish novel', but based on the words in the title, we can make some assumptions. 'Ishq' is love in Urdu, and 'aatish' which can be translated as fire. So the main theme might revolve around a love that is as fierce as fire. This could mean that the story might be about a love that is difficult to control, that burns brightly and perhaps causes both joy and pain. It could also be about how this intense love affects the characters' lives, their decisions, and their relationships with others. It might show how they navigate through the heat of this love, whether they get burned or find a way to make it a positive force in their lives.