There is no walkthrough for AQW as it is a constantly evolving game with many different areas, plots and side quests.
No, you can not be invincible in AQWorlds.
You can not. AQworlds does not have a trade system.
There are multiple kings in aqworlds.
You can only have one armor on at a time in AQWorlds. You cannot combine armors in AQWorlds.
Kuro is the boss in the river in aqworlds.
The walkthrough can be found on YouTube.
There is a written walkthrough, and a link to a video walkthrough, at the related question below.
download the aqworlds battle bar
There is a written walkthrough at the related question and a video walkthrough at the related link.
You can't exactly be a Guardian on AQWorlds, but you can verify on AQW that you have Guardian on the original Adventure Quest and get Guardian class in AQWorlds. :)
You cannot be a ranger in AQworlds. It is not currently an available class.
AQworlds is based off of Eastern time in the US.