1) What is the difference between the magic power from "Guardian of the Secret" and the "Primal Magic"?
2) Does the magic power of "Primal Magic" contribute to the hero's total magic power?
3) Why bother increasing magic power and spending precious skill points on it? If magic power doesn't affect popular spells like "Time Stop," "Charm," "Dispel Magic," and many others. For example, "Charm" always lasts 1 turn, "Time Stop" lasts 2 turns, etc.
4) Maybe it's enough to just use the default settings that the computer uses?... Will "Charm" still last 1 turn if the magic power is 10 or 30?
5) And what does magic defense even affect? What does it protect against?...

1. "Guardian of the Secret" increases the hero's magic power, while "Primal Magic" increases the magic power of "Primal Magic."
2. No, it doesn't.
3. The hero's magic power increases the damage of your creatures that have magical attacks. However, spells like "Time Stop" and "Petrify" can also last for 4 turns. Also, "Cleanse" is a great spell for humans that depends on magic power, and many other spells are improved.
4. Again, many spells are improved, and the damage of your creatures with magical attacks is increased (for example, succubi, radiance, vestals, etc.).
5. Thanks to magic defense, your troops will take less damage from creatures that attack with magical damage. Also, the more magic defense your hero has, the greater the chance of making "Time Stop" last 1 turn for your opponent.