Unless I totally miss my mark, the more espers a person has the stronger they are right?
Like, if I stacked the Fire giant, the Ice mermaid, and the Lightning dragon on one person, the giant would be tier 1, cost 1/3 of your MP, and be about as strong as you, the 2nd would be stronger and cost 2/3 of your MP, etc.?
I just hope you can't out and out miss some of the 13 non-mandatory espers..