Eli is pretty usefull for hard mode
Got 2 legendary items on her (sword and shield) and she has nearly 1.000.000 hp, 1.000 def and about 150.000 atk.
So she is a realy nice tank for most of the dmg (but very very slow...)
Im farming on hm 10 atm cause its realy nice to lvl up your maidens (45k exp per clear)
And my maidens are lvl 55, 55, 54, 44 so if you could manage to equip a tank pretty well you should be able to beat the first stages of hm without any problem to lvl up your maidens and obtain some better equip for them