Otherworldly Patron: The Dead King [ROUGH DRAFT]

The Dead King or Queen is a powerful entity with sway over undeath like a dead god, lich, or death knight. Whatever the nature of this creature, it is willing to make pacts with mortals to imbue them with the ability to cast potent necromantic spells, creating warlocks in life that will serve them in death.

Mortals may make a pact with the Dead King in order to more fully master life and death, or to attain the reliable protection that only a handful of loyal undead can provide.

Special Mechanics:

• Death-themed spells that fit within warlock spell slot schema.
• Gravesense - Cast speak with dead at will at first level, know where dead folks are.
• Master of Death - Cast empowered animate dead once daily. Balanced to be roughly identical to the necromancer wizard's level 6 feature.
• Bone Armor - When a minion is next to you, you can cause it to take half the damage from an incoming attack twice (scaling up to three times) per combat, with a tHP bonus if this kills the minion.
• Corpse Explosion - Instantly kills a minion to deal 9d6 (median 31.5) damage + poison to adjacent non-undead creatures, save takes half. Is able to be activated as a reaction on a minion's death, refreshes with a short rest. Balanced off of Cone of Cold, as warlock short-rest level 14's are approximately similar to a slightly-better-than-level-5 spell. 

Balance Concerns:

• Master of Death giving a warlock a buffed animate dead as a class feature leans strong for a level 6, but important to the progression. This is counterbalanced somewhat by both the level 10 feature and the level 14 feature actively weakening the in-combat ability of Master of Death in order to function, the first of these arriving just after Master of Death can be cast with level 5 slots.
• The verbage of these features opens the up to synergy with the Mystic Arcanum (level 6 spell slot) option create undead, but this is intentional and I can't (yet) see any way in which this could be abused.
• Bone Armor's tHP bonus may be a bit much, but it's intended as a trade-off for both its limited uses and how it actively harms a minion.
• Corpse Explosion is the only level 14 damage short-rest ability. As said above, it's (about) a level 5.5 spell, balanced off of Cone of Cold + a status effect. When compared to the fiendlock's level 14 Hurl Through Hell (long rest, single-target, 1 turn removal, no save, median 55 damage), the ability Corpse Explosion (short rest, multi-target, no removal, costs a save, median 31.5 damage) does ~45% less damage, is better on two counts and worse on two counts. About as balanced as I can make it given the incredibly diverse nature of level 14's. 

Version 0.1 (rough draft)

Link to the reddit thread.