The most useful ability for koi warrior is the Flare to beat him. And use like 2 ylanas blaster or something and most importantly a healer. A good one like a jar of rejuvenating brains is enough i guess. Those are some of the set that i use to beat Koi warrior back in the days with pretty average stats. Around 80 each for STR and DEF
Thank you, I haven't used the BD in years. Had no idea you get rewards now.