Effie vs. Hardin

Effie has... more chances of merging compared to Hardin considering he's a 5* exclusive and she's not.

Effie has more attack than Hardin, but less defense and way less resistance.

Hardin has a Distant Counter weapon.

Hardin is overrated, i have and never use him. The DC on his weapon is rarely useful and he requires steady breath and the qr seal to shine, to much rss. My +atk effie is an mvp with slaying lance dc glimer she just one shots non greens. Warry fighter is still verry stong skill, only Gronblade or lancebreaker can one round her.

Hardin can function as a Res Tank in Armor Emblem which is very rare for a melee unit nonseasonal. Effie serves as a stronger player phase with Bold Fighter which can get pretty out there. So he's good, but you don't need to sell your kidney for it.

Hardin can function as a Res Tank in Armor Emblem which is very rare for a melee unit nonseasonal. Effie serves as a stronger player phase with Bold Fighter which can get pretty out there. So he's good, but you don't need to sell your kidney for it.

Hardin:
basically can has everything you wish for in a unit - DC plus very very solid mixed phase set. DC is really useful in terms of coverage, and since he has such high BST to begin with, he can really make it shine.

Effie:
Higher atk (though Hardin with breath skill can have guaranteed special proc in both phase), way easier to merge, more accessible. Practical wise since armor unit mostly rely on enemy phase, she is almost as good as Hardin, with higher merges she can be better than unmerged Hardin.

Conslusion:
unless you are a whale, you don't need Hardin if you have Effie, but one Hardin for PvE content is just too convenient :p