Azash, the Eternal

This custom patron for the warlock is built around melee oriented characters, such as Pact of the Blade warlocks. 

Eternal Boon

Starting at 1st level, when you reduce a hostile creature to 0 hit points, you gain temporary hit points equal to your Charisma modifier + your warlock level (minimum of 1).

In addition, when you make an ability check or saving throw, you may add a d10 to your roll. You can do so after seeing the initial roll but before any of the roll's effects occur. This particular feature may only be used once per rest.

Azash's Grip

Upon reaching 6th level, you learn the spell Vampiric Touch; it doesn't count against your number of warlock spells known. Whenever you cast Vampiric Touch, you deal additional damage equal to your Charisma modifier (minimum of 1).

In addition, upon scoring a critical hit, you regain hit points equal to the amount of damage dealt, rather than half. This effect cannot occur more than once per long rest.

Gifts of the Eternal One

Starting at 10th level, you gain the ability to beseech your Patron for aid. At the end of a rest (short or long), choose one of the following benefits. This benefit lasts until the end of your next rest, or until you dismiss it (no action required).

Hellish Vitality: You gain temporary hit points equal to your warlock level + your charisma modifier.

Might of the Legion: You summon a Death Dog to do your bidding. In combat, it shares your initiative count, but it takes its turn immediately after yours. It can move and use its actions on its own, and will fight alongside you unless commanded otherwise (no action required).

Chosen of Azash

When you reach 14th level, you take your place among the ranks of the undying. On your turn, you can use a bonus action to regain hit points equal to 1d8 + your warlock level. Additionally, if you put a severed body part of yours back in place, it reattaches itself.

Once you use this feature, you cannot use it again until you finish a short or long rest.