The Griffin's Crier

Dwarkarnytor (Axe of Our Fathers, Axe of the Clan Soul)
Weapon (dwarven war axe), legendary (requires attunement by a dwarf of lawful alignment)

Dwarkarnytor is an intelligent weapon obsessed with the preservation and defense of the dwarven race and its culture. As such, it can only be wielded by a dwarf of lawful alignment. You gain a +3 bonus to attack and damage rolls made by this magical weapon. It has the following additional properties:

Ancestral Cohort: Once per day the wielder can summon the embodiment of dwarven culture to fight alongside him or her in battle. This creature takes the form of a lantern archon. This power is renewed at dawn.

Preservation of Knowledge: Whenever you make an Intelligence (History) check related to dwarven history and culture, you are considered proficient in the History skill and add double your proficiency bonus, instead of your normal proficiency bonus.

Sentience: Dwarkarnytor is a sentient lawful neutral weapon with an Intelligence of 16, Wisdom of 14, and Charisma of 18. It has hearing and darkvision out to 60 feet. The item can speak, read, and understand Dwarven and may communicate with its wielder telepathically.

Personality: The axe seeks to defend the dwarven race at all costs, and is eager to take on challenges that include defeating racial enemies, recovering lost knowledge, or liberating ancestral fortifications.

The original version of the axe required the wielder to take levels in a dwarf-specific prestige class, but prestige classes don't exist in 5e, so that's a non-starter. I think the attunement requirement gets at some of that, by necessitating that it's one of the only magic weapons you regularly use.

The ancestral cohort ability summons a lantern archon, which does't exist in 5e but seems pretty ease to convert. I also thought that perhaps having an earth elemental (appearing like a dwarven warrior carved from stone) might be more thematically appropriate.

What do you think?

I like it. The prestige class stuff was a 3e idea that sounded a little better on paper than in actual play. And honestly, around the time that we would get those type of items, we would hardly play the characters any more anyway, so it wasn't functionally different than having a +3 weapon with some flavor text.

The Lantern Archon ability was to represent one of your ancestors coming to aid and advise you. I think that could take a few different forms in 5e. We could port in the guardian spirit type ability from SW:Saga (obi wan appears from time to time to clear up some lies he told you previously). But I also like the dwarven shaped earth elemental emerging near you and following you around a bit.

Whatever seems more fun for you to play is how that should convert.

Earth elemental in the shape of a dwarf.