Do spells from your secondary schools do less damage than if it was your primary (unbuffed)?
Hey Dakthorn. Secondary spells do whatever damage is listed on the card. The big disadvantage is that you can only use power pips on spells from your primary school. You can buff your secondary spells if you learn the necessary buffs. If you find that you are using primarily one second school to augment your primary, then I would also recommend choosing gear that can assist (in terms of damage and accuracy) both school. Much of the crafted gear does that. Its mostly a question of personal taste.
No. The damage numbers on the card is the same regardless whether it is your primary or secondary school.
However, in some cases, you are not able to learn a secondary school's blade, trap or aura. Additionally, school-specific equipment only give boosts to that particular school, and you can only wear school-specific equipment from your primary school.
The base damage of a spell does the same damage regardless of your primary school. The only adjustments to it are spell buffs and item buffs that will make it more powerful then the base damage range.
