Great game - end game tips
I can see how early players may miss rebirth, which gives you a currency that can raise your % rates and/or buy new characters. It’s found on far right tab
I prefer to farm lvl 40, “hidden cave” early on because it gives higher gold drops. Hopefully you will get gear with gold/exp/drop/crit/evade at this stage because it’ll be low level, thus cheap to upgrade with your gold.
I’ve found farming at lvl 290, “eternal place” and lvl 470, “hidden coast” are most rewarding but only if you can clear the monsters quickly enough.
Walburga is the best farmer - he does both tank and damage across the entire row on turn 1, so well worth it to get him asap. Make sure you get some “hit” gear to compensate for the axe having -20% hit.
Evade and guard can work very well on most characters. Front line tanks need it.
Good luck!