ToME: the Tales of Maj'Eyal

Tooltip notes that there are trainers that can unlock categories.

1. Do they do this by granting category points or by unlocking a specific category? I unlocked a lot of additional skill trees as my current Summoner but don't have the category point to make any use of them. Am I borked?
2. Outside of lost hope, where are there trainers?

1) Made specific categories avaliable...although some needs category points to be spent on...

2) Random rescue quests...eat Sandworm queen's heart, side with Ralorean and destroy Zigur...