May or may not be a good idea but I’ll write it down anyway:
A hero that you keep in your inventory that increases attack or health of all heroes by 1% permanently? (when fully ascended)
A hero that has no mana bar in-fight but provides permanent +10% mana regen for adjacent allies at max special skill level (when fully ascended)
A hero that makes Little John’s special skill very fast but offers no other in-battle benefit eg Little John’s wife. (when fully ascended)