Askr Trio

Endgame PvE... no way. You would have a really hard time even clearing the top level of the training tower with them. They are outclassed by dozens of other units at this point.

Alf has some pretty unique brazen stacking, so he could be made powerful, and Anna has some support potential. But they really need the arena bonus to their stats to be competitive.

With Divine Dew so hard to come by, Alfonse is the only one I have refined and I went with the Res refine. Your dew is really better used elsewhere unless you really need a bonus unit.

Alfonse with the brazens can be pretty brutal. Like, Folkvangr+res, brazen def/res, brazen atk/res, brash assault, atk smoke, and bonfire, ignis, or galeforce. 46/40 defenses with over 60atk.

Sharena with the Fensalir refine probably works pretty well. I haven't tried but she can get her spd well into the 40s with solid def and trade hits over many rounds, maybe use renewal.

Alfonse is pretty great overall if you build him right.

Sharena is by far the best askr unit if you actually use her right, mine gets +15/+16/+16/+22/+19 added to her stats while in the arena.

Anna has trouble staying alive due ot having shit defense.