Cathamber / Arc Zeekhad

You get XP as determined by the GM at the end of a "session". (This is a rather nebulous division. Don't sweat it.) As you gain XP, you can spend it on the following:
Gain 1 HP - 6XP
Gain Weapon Proficiency Group - 8XP
Gain Mastery of Weapon - 8XP
Gain Trait - 10XP

You will typically get 1-3 XP per "session". (Again, "session" is a bit of a nebulous term.) Elsewhere Psybermagi lists what you get XP for.

There is no limit on the number of XP you can gain as a character. There are no "levels", either. The only standard limit is that you can only have a maximum of seven chosen Traits. (I.e. you don't count any traits you gain from your heritage.) Once you have that limit of traits, then any trait you gain requires it to replace an existing one. Other than that, there aren't any limits that I am aware of.

But it does take a while to get all of that. ForeverDED (Blornvid) and I (Skeeve) have been here longer than anyone else, and neither of us have quite yet reached our Trait limits. So, it does take a while to get there.

Thanks again Daryen!
This looks very promising, hopefully our team will have some kind of rest after this library event.

I moved weapon mastery up next to proficiency

Thanks!

Another question - sorry to have so many lately :) - If Arc takes the Druid Trait two times, so as to have two animal companions... How does it count for the purpose of the 7 traits limit? Does it count 2, or 1 (with 2 companions).

That would be two Traits.

For example, Skeeve has taken Archmage twice for different sets of magic abilities. That counts as two separate Trait choices.

I'll roll random magic tonight and let you know.
FYI Potter's clock is legendary. You won't find it in a shop.

Basics of Psionics could be studied in the library