Darkblade: Optimizing a Devil's Sight Hexblade

[Laserlight]

TL;DR: build a lvl 6 hexblade/whatever to use Darkness and Devil's Sight

In Storm King's Thunder, I have a Fighter 1 / Hexblade 5, and the DM has approved our rebuilding our characters more or less from the ground up, as long as we keep the same general concept. He needs to be a melee focused hexblade (and, out of combat, the Face), but I could, for example, rebuild him as Vengeance Paladin 3/Hexblade 3, or Shadow Sorc 4/Hexblade 2.

What I need to keep:
Stats: 15 13 18 11 12 18
SCAG variant Tiefling (Vicious Mockery, Charm Person, Darkness in lieu of Infernal Legacy) who is in the lineage and service of Shar, Lady of Darkness (domains Death and Trickery).

I don't expect the campaign to continue past the end of SKT; the build should work for L6-L10. Rest of the party includes sharpshooter ranger, sentinel bearbarian, assassin, whisper bard, and occasionally an open hand monk.

Thus far I've been using Duellist, longsword and shield (because giants seem to have a high attack bonus, even with Disadvantage). His pact weapon is +1 magic. Including one free feat, he has Mobile and Warcaster; I could see replacing Mobile. Cursebringer invocation is seen as having been replaced by Eldritch Smite.

Cantrips: BB, Minor Illusion, Vicious Mockery (from Tiefling) and EB; I'm trying hard to avoid "Just Spam EB"
Incantations: MoMF, Devil's Sight, Thirsting Blade

If I've done my arithmetic right, Darkness is more advantageous (from both attack and defense) than Hex, even though I'd love to have Hex up too; and when you include Eldritch Smite, it appears Extra Attack is better than Booming Blade (particularly if BB wouldn't proc anyway because the giant is already next to our barbarian and doesn't need to move).

[CursedRhubarb]

Looks like you've a pretty decent set up as is. I'd just say be careful with the DS+Darkness, especially when being a melee character. While it tends to help you out, it can hinder not just the enemy, but the rest of your party as well. It can stick them with disadvantage on their attacks and prevent spell casters from using a lot of spells on enemies. Then when you have an enemy with a high attack bonus like a giant so disadvantage doesn't prevent too many attacks, it can actually help your enemies and has a possibility to open up an accidental tpk.

[Laserlight]

Looks like you've a pretty decent set up as is. I'd just say be careful with the DS+Darkness, especially when being a melee character. While it tends to help you out, it can hinder not just the enemy, but the rest of your party as well. It can stick them with disadvantage on their attacks and prevent spell casters from using a lot of spells on enemies. Then when you have an enemy with a high attack bonus like a giant so disadvantage doesn't prevent too many attacks, it can actually help your enemies and has a possibility to open up an accidental tpk.

That's the standard disclaimer to Darkness, but in fact it hasn't caused a problem. I have to pay attention to maneuvering--usually darting in to attack and back out so the target isn't covered by Dark--but I'm fine with that. It would be awkward in small enclosed spaces, but we're fighting giants.