Blacksmith of the Sand Kingdom

I was able to auto battle almost the entire boss re-fight easily using 3 Samurai/Thief party members on the front-line and 2 Elementalist/Sage members on the back-line in the Grand Attack formation. The only non-auto battle I had to do was to cast Faerie Veil once every 2 turns against the later bosses to keep them from hitting me.

I used the MP Recovery passive and Auto MP Recovery +10 runes on all characters for infinite mana, stacked Luck and Evasion runes on all armour and Evasion on the Accessories, as well as the 100 Luck passive for all characters and Evasion Vanguard for my 3 Samurai. My 2 Sages (used Elementalist as primary to let them equip heavy armour) used Daggers and the Shield passive to let them equip Mana Shields for even more mana recovery, although this was probably overkill, everyone over-regenned on mana and stayed at maximum. The final key was using Abnormal State Resistance passives on all characters with Ngunesis of Misery faith to make myself immune to all statuses.

Overall I found the battles very easy, like I said only really stopped auto battle every 2 turns to have my main character re-cast Faerie Veil then right back to auto battling. The auto battle AI was really bad too and split damage so I wound up killing both final bosses within 1 turn of each other, so on manual battle it would've gone much more easily.

Stat Wise my Samurai had 810 evasion and my Elementalists had 550 and everyone was able to dodge 95% of attacks.