I stayed in orc 2 til about 94 with my amistr, until I got the 4th skill, then I moved to churchyard. You could try churchyard w/o the 4th skill at 90+, but I'd recomend orc 2 for as long as possible.
Another good option, if you're willing to play actively is bathorys. They have low hp and decent xp, best way to do it is (since they are demi human I assume u have toad/cranial) is to rest your pet, gather a mob, and call it out and tank all the bathory for the amistr. The down side to this tho, is your homu gains intimacy slower, because when ever you rest or fly wing, your homus hunger timer resets and it takes another full minute for his hunger to go down one. But another pro is bathory cards, and occasionally you can snag a good drop from the sword mini bosses on the same map

good luck