How is exp determined from battles?

It seems, like honor points gained from battle, to be determined from the respective difference in honor points. This does make sense, but the ratio is just bad. Fighting anyone from top 1000 rank with my honor points around 6k, I get 12 exp. Fighting anyone at my level, I get 1-2 exp when their honor points are <4k. With this rate, it seems leveling takes very very long. However, I see people with low honor points, and they are level 100+!

How are they accomplishing this? Is it that they buy shit tons of EP's and grind through the missions? Or is exp calculated not only by the difference between you and your opponents honor points, but the BP/level of the monsters involved in the battle?

It's calculated by your level vs their level. Fighting someone of the same level or lower gets you 2 xp, xp goes up for every level higher they are from you.

I believe the exp formula is:

XP = 2 + Max(0, opponent level - your level)

So if you are level 10 and your opponent is level 15:

XP = 2 + Max(0, 15-10)
XP = 2 + Max(0,5)
XP = 2 + 5
XP = 7

If you and your opponent are both level 10:

XP = 2 + Max(0, 10-10)
XP = 2 + Max(0,0)
XP = 2 + 0
XP = 2

Yay math!

max xp of 12