THE SUMMONING SYSTEM
It works on the basis of the power level of the summoning mage.
This is how ranking works for humans:-
level 1-19 is Beginner
level 20-29 is Novice
level 30-39 is Commander
level 40-49 is Erald
level 50-59 is king or a queen
level 60-69 is Demi-Gods
level 70-89 is commandments of God
level 90-100 is God Level
For Demons Ranking is as follow:-
level 1-19 is common troops
level 20-39 is general of the army
level 40-59 is Banner Holder
level 60-79 is Demon Lord
level 80-100 is only one entity who was able to achieve it, Sandar Gletch
Summoning is done by the combined power of the crystal, the magic of the kingdom and the summoning mage leader, since the summoned hero is capped based on the mage leader every kingdom prefers a summoning mage guild whose leader ranges from 30-39 for moderate output.
The prime magic used by several Demon Lord is Myalo Elanchos or mind control.
Holy magic to humans is only accessible by the heroes and Kings or queens.
God level magic can be only learned by slaying a God and the obtained magic will be the same as that which was used by the forth mentioned slain God. This task is hero specific.
Other small and handy magics can be manually brought or upgraded via the dialogue prompt.