The combat damage is essential for fighting - you can hit your opponent a hundret times, but if you only scratch him, you will loose.
There are only two things influencing the damage:
We have developed a formula that shows it exactly:
combat damage = strength * weapon damage / 20
e.g. Strength is 200 and your weapon's damage is 20-35 you will make 200-350 combat damage per hit.
You can try different numbers with this tool: http://ro.shacknet.nu/gondalrechner.html
"Waffe"= weapon (weapon damage)
"Atk" = attack (combat damage)
"Str" = strength