1. Can Godtiers die of age? 2. Did other universes exist before the trolls universe, 3. and what happened to them? are they gone, how? 4. The green sun is like the sun for all universes that has, does and will exist?

1. Godtiers are immortal so no.

2. Yes, we just haven’t heard about them in-comic.

3. We just don’t know. 

4. The Green Sun is an enormous sun and instead of planets revolving around it, there are galaxies revolving. Dave and Rose created it when the blue and red bomb inside the Tumor went off. It was fueled by two dying universes. The trolls’ universe died when Spades Slick shot Snowman and the humans’ universe died when Bec Noir used Red Miles on the Genesis Frog.