The best overal hero in Soul Seeker: Six Knights is Magic Sword Irene. She is available in both light or water element and has powerful synergies for each of them. Irene is a high-tier hero with incredible close-range battle skills. Her attack speed increases as she fights allowing no chance of a counterattack from her opponent. Irene will definitely be a valuable asset to any team when battling opponents.
Magic Sword Irene can also be used in the following dungeons.
Dimension Gate:
Advanced Hero Dungeon
Special Dungeon:
EX Stage of Bravery Dungeon