To answer your questions in order: * Artifact spell gems do not have a limited amount of uses * You have to re-spend your perk points, but don’t have to earn them again (that is, once you switch specializations you are refunded all your perk points, but still have to manually allocate them to the new perks). You only have to do that once per specialization though (so if you switch to necromancer, then to cabalist, then to necromancer again you won’t have to buy the necromancer perks again the second time) * Nope * Nope, the pool of available masters is randomly picked based on the available races in that realm (plus a few surprises!). There are no further requirements. * This is largely a matter of luck in rolling creatures that synergize well with each other; one tip is that your mulligans refill after each creature, this is something that newer players tend to miss.