If existence is the only case, why do relationships matter so much? You can exist witout them, but not truly live without them from my observation.

if the Devil tortures and burns all being in hell, do devil worshipers burn as well? why would they do that? does the devil care if he has followers?

it always seems like the devil has the most fun.

In my opinion, the meaning of life is to live. Life is a collection of experiences, both good and bad. Its a matter of perspective, if you just live to experience as much as you possibly can then life doesn't need meaning because you're just enjoying life as it happens. Even when everything is going wrong, you can look back at those experiences and know that you are living a full life.

Our minds have a finite processing power, why must it be within our comprehension what life is for when we don't even get how it works properly yet? Think of it like any foreign technology, you could try and determine what it's for by looking at it and thinking what you would design something like that for, but this is a flawed methodology. Instead, we should be looking at reverse engineering, taking everything to bits then putting it back together again, taking into account what everything is for. Presuming the creation can understand the creators motives, that is. Ever wonder what a computer would think if you tried to explain to it why you made it?

A purpose in life is to have a purpose in life

http://www.marcellosendos.ch/comics/ch/1989/11/19891110.gif

The purpose of life is to turn into plant food.

Your comic reminds me of this illustration: http://www.wired.com/wiredscience/2010/02/what-is-time/