The Eldritch Maul ability says:
each of your melee attacks with a weapon or an unarmed strike can reach a target up to 15 feet away from you, as inky tendrils launch toward the target. In addition, your melee attacks deal an extra 1d6 force damage on a hit.
So, let's say that I'm using the Eldritch Maul ability with a normal shortsword to melee attack a target that is 15 feet away. Is it only the inky tendrils that hit the target, dealing just 1d6 force damage, or should I also factor in the 1d6+STR/DEX piercing damage of the shortsword as if it hit the target as well?
Follow-up question: If the weapon was magical, would its magical properties factor into the attack?
For example: Would your attack with the Eldritch Maul ability benefit from a +1 weapon?
In another example: Would a Dagger of Venom's poison property proc on a melee hit from 15 feet away while using the Eldritch Maul ability?
Dagger of Venom says:
You can use an action to cause thick, black poison to coat the blade. The poison remains for 1 minute or until an attack using this weapon hits a creature.
Best Answer
Your reach increases for that attack.
The rules for Melee Attacks state:
Eldritch Maul says:
So if the shortsword is your weapon, Eldritch Maul says your attack with that shortsword can reach a target up to 15 feet away: your reach for that attack is 15 feet.
Everything that normally happens when you attack with the shortsword from 5 feet happens, the attack deals an extra 1d6 force damage, and you can attack a target up to 15 feet away, instead of the usual 5.