Raven Queen warlock

[Loudmuzak]

So...
I'm making a PC for a one-on-one mini campaign prequel to a full length/party campaign.
I will start at 4th level with randomly rolled stats (7-16-11-13-14-16, order can be changed freely) and the build must include at least one level of Warlock with the Raven Queen pact. I'm envisioning the character as a "celtic" style warrior witch (fits well with the setting), using a spear and no armor to speak of.
Any suggestions for a build that will be viable for a few levels of solo play would be greatly appreciated.

[Herobizkit]

Monk 2/Warlock 2 could be a hoot.

S: 7 D: 16 Co: 13 I: 11 W: 14 Ch: 16

Monk gives you an AC of 15 with no armor. Spear counts as a monk weapon for flurry purposes. Ki will help you get into/out of tight spots and drop some extra hurt AND Ki recharges on a short rest, like your other Warlock powers.

Warlock 2 is what you make of it. No lack of options there... a purple d10 'hadouken' is cute.

Consider going Monk 3/Warlock 3 for their Archetypes. Shadow Monk with a Sprite (Unseelie?) familiar could be swert.

[Captain Morgan]

Another option would be a Hexblade, which are also linked to the Raven Queen but get a much nicer package for melee. Armor of Shadows works for going armorless and nets you +1 over a monk, and you can apply charisma to attack and damage rolls as long as you wield the spear one handed. 3 levels of Warlock will nab you the Darkness/Devil's Sight combo and you won't have to deal with crippling your party to abuse it.

If you want to save an invocation you could find out if your DM will still let you get advantage from seeing through an imp familiar's eyes. Remember, imp can shapeshift into a Raven.

Assuming those stats are pre racial, a pure Warlock can get 20 charisma by level 4. Compared to the monk multiclass you can have better accuracy, spell access, a pact boon, and more hit points since you don't need need WIS. If you go Pact of the Blade you can snag yourself extra attack at 5th and/or an automatic +1 enchantment to your weapon.

[Ferrin33]

You could go for a Warlock2+/Sorcerer3+, taking Raven Queen for warlock, and Stone Sorcery for sorcerer. Would give you shield proficiency and makes you rely purely on Con and Cha. If you'd take the War Caster feat you can wield both a spear and shield while casting Eldritch Blasts and quickened eldritch blasts. Perhaps flavored to come from the tip of your spear. Your skin could look like marble from the 'Stone's Durability' class feature or whatever stony look you feel like.

If you want to be melee-oriented I can't recommend raven queen/stone sorcerer, warlock/paladin would be a better option for this. I would urge you to ask your DM to maybe get a special martial proficiency spear with the finesse property in order not to become MAD. The alternative is not using a spear and either use a quarterstaff with Pact of the Tome(Shillelagh cantrip), or a rapier and go for dexterity.

Another option is to go Pact of the Blade, and homebrew an invocation along the lines of the other weapon invocation that let you add 2d8/spell level to your attacks. For example; Pact weapon is a spear with Finesse, and like the other invocations lets you add 2d8 piercing/necrotic damage per spell level of a slot expended on a hit just like the others. If you go this route, you can go full Warlock with Pact of the Blade and the Raven Queen patron.