All romances are optional as well, which wasn't the case in previous versions of Persona 3 (except when playing as the Persona 3 Portable-exclusive female protagonist), and it's pretty wild to think back and realize you used to be forced to have a relationship with every female classmate ...
Messiah's affinities change with each successive game in the Persona 3 series: In the original P3, Messiah had just Repel Light and is weak to Darkness for its affinity chart. In FES and Portable, Messiah was buffed to have a resistance to all magic, though retaining the previous affinities...