I just completed this quest, but i'm a bit confused. There's no follow up with the Jarl about his son? The quest did start off with him wanting me to seek his son. Then I just got this Ebony Blade, but what exactly does it do? Does Mephala have a shrine anywhere, or was the only contact with her through Dragonsreach?

Anyone?

This is the hints and tips section?

once you get the sword, the quest ends.

You can make the sword more powerful if use the sword (kill someone) on somebody that trusts you, like a companion

Or someone that you've done a quest for.

Thanks guys. What does the sword do? What enchantments does it have?

Sadly, no there is no follow up with the Jarl and his son, You might be able to go talk to him but I never did.
The Ebony blade feasts of deceit (sp?) which means to kill people that trust you, ex. Killing Lydia because she's your house carl and trusts you. (It's what I did)
The map that came with the strategy guide shows no shrine for Mephala so you're only contact is through the sword itself, not Dragonsreach's cellar.