so for a melee fighter hardcore

whats the point of the acc charm?

as with any other character, you can equip a heal charm there and heal yourself during battle. this cuts down on regen time and can improve the amount of kills per regen.

If all else fails you can just use it as an extra slot for charms. stick one on the acc slot and you can pick up 1 more item

you will not reach high healing rates like a caster, but some healing possibility can bring you victory
in close fights although you will most likely just have the mana pool for some casts.

its a good method to shorten regen periods, summon a level 1 monster and heal with the charm,
kill the monster with the weapon once your mana is empty and then go on fighting.