About D Spheres
They all lean toward granting party auras when certain conditions are met.
Keywords for the abbreviations below are referenced at the bottom
What is best?
Every character is different, but there are some general rules
Attack auras are generally preferred, especially supports that are attack oriented
mBRV & iBRV should synergize with the character's kit, if they grant battery or BRV regen, boost the relevant stat
ATK Aura D spheres
These are generally the only D spheres you ever need. ATK aura is best, just make sure your character can reliably trigger it!
mBRV, iBRV, & HP Aura D spheres
Freya sphere is the "best" D sphere for characters that deal damage based on their or the party's HP stat, such as Porom and Lenna. The rest are junk.
Keywords used under character images:
broken enemy - when attacking a broken target or breaking them
#+ buffs - when the character has at least that many buffs
buffing - when granting a buff
self healing - when healing your own HP