I would like to mention I have a head cannon:

When players travel between servers, they are separate lives. This happens when they die (very rarely without), hence the different lives. So an example would be Grian has memories of a past life from a place know as Evo (Evolution SMP). Not all players have past lives. Some players remember more than other, heck, some don't remember at all (which is rare). Most don't remember too much. This is a thought I had while brainstorming and I think it fits into some of my stories but this !

Hope you understand!!

~Swoopy