Greetings fellow adventurers, today I come seeking advice on where I should allocate some stats/what feats I should pick up for a Hexblade NPC I'm building for a game I'm DMing.

For some context, she's a half-elf (Drow ancestry), at seventh level, sabre (finesse) as her pact weapon, who's the bodyguard/melee support of a wizard NPC.

Now, the way I envision her playing is something along the lines of a dodge-tank/frontline fighter while the wizard supports her from the back/crowd controls. While her spell castings would focus around extra damage for her melee attacks (booming blade, smites, etc.) or imposing disadvantage on enemies/advantage on herself and allies (faerie fire, darkness (has devil sight), etc.).

So with that in mind, what stat, besides charisma, would be a better investment, Dex or Con?

And what feats do you think would work best with this concept? Elven Accuracy and Sentinel seem fitting, but what about War Caster or Defensive Duelist?

Thanks in advance for your input, and may the chests you find always be bereft of teeth and tongues.

7th level with Elven Accuracy puts you at 18 Cha, very nice, and only a level away from a +2 Cha ASI for 20 Cha and max modifier on spells and melee. Do it, don’t delay, there’s time enough for Warcaster or Tough at 12.

14 Dex is enough for a Hexblade in medium armor, that and a shield gets you to a respectable 19 AC, or an acceptable 17 without one. Bumping Con to 16+ is more valuable, for more HP and better Concentration saves, then chasing Dex AND Medium Armor Master.

Other fancy feats like Sentinel or Defensive Duelist... that isn’t really a priority, but you could fit them in at 12 instead of Warcaster, or better yet, long after that at 16 or 19. Don’t get too fancy with your build, and a plain old Hexblade does great. 

Oh this is an NPC? 

Don’t build it with class levels and features, just make a monster. 

If you are only going to use this as an npc, Then just make a monster stat block. No need to go into such detail as class levels on an npc.

If you or one of your players are planning to play this as a full character at some point then use con as your defensive stat over dex. If you want to be a skirmisher(dodge tank) or a front line fighter (tank), pick Con. Skirmishers and tanks rely on absorbing damage more than avoiding it because they spend more time in melee combat. If you pick dex over con, you would operate better as a hit-&-run fighter more like a rogue who tries to avoid damage. 

As a Hexblade you don’t need a dex bonus greater than +2. So for a half elf stats (10 14 16 8 12 16 ) standard array after modifiers. Those stats work for an npc monster stat block too. Wear the best medium armour you can get and use a shield with your Sabre. Max out your Cha before looking at feats unless you really want the flavour the feat gives.