Psionic Mind. Morlin can send telepathic messages to any creature he can see within 30 feet of himself. Morlin doesn’t need to share a language with the creature for it to understand these messages, but it must be able to understand at least one language to comprehend them.

Inured to Undeath. Morlin's hit point maximum can’t be reduced.

Halo of Spores. Morlin is surrounded by invisible, necrotic spores that are harmless until you unleash them on a creature nearby.

Undead Thralls. When Morlin casts animate dead, he can target one additional corpse or pile of bones, creating another zombie or skeleton, as appropriate.

Whenever Morlin create an undead using a necromancy spell, it has additional benefits:

• The creature’s hit point maximum is increased by 10.
• The creature adds Morlin's proficiency bonus to its weapon damage rolls.

Multiattack. Yunkatel Morlin makes three Staff attacks. Morlin can replace one attack with a use of Spellcasting or Breath Weapon.

Staff. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 3 (1d6) necrotic damage if Symbiotic Entity is active.

Spellcasting. Morlin casts one of the following druid or wizard spells, using Wisdom or Intelligence as the spellcasting ability (spell save DC 17, if the spell is on both class lists, he may choose which ability score to use as the spellcasting ability):

At will: chill touch, druidcraft, primal savagery, thorn whip, produce flame, mage hand, prestidigitation, mind sliver, toll the dead, sword burst

3/day each: vampiric touch, control water, create or destroy water

2/day each: animate dead, blight, bane, wither and bloom, gentle repose, shatter

1/day each: commune with nature (as an action), antilife shell, circle of death, animate objects

Breath Weapon (6/Long Rest). Morlin exhales yellowish necrotic energy in a 15-foot cone. Each creature in that area must make a DC 15 Dexterity saving throw. On a failed save, the creature takes 22 (4d10) necrotic damage, half as much damage on a successful save.

Symbiotic Entity (2/Day). Morlin channels magic into his spores, gaining 40 temporary hit points. While this feature is active, Morlin gain the following benefits:

• When Morlin deals his Halo of Spores damage, roll the damage die a second time and add it to the total.
• Morlin's melee weapon attacks deal an extra 3 (1d6) necrotic damage to any target they hit. (Included in this stat block)

These benefits last for 10 minutes or until Morlin loses all these temporary hit points.

Spellcasting (Bonus Action). Morlin casts one of the following druid or wizard spells that has a casting time of a bonus action (spell save DC 19, if the spell is on both class lists, he may choose which ability score to use as the spellcasting ability):
3/day: healing word

Gem Flight (1/Long Rest). Morlin can manifest spectral wings on his body. These wings last for 1 minute. For the duration, Morlin gain a flying speed equal to his walking speed and can hover. 

Spreading Spores. While Morlin's Symbiotic Entity feature is active, he can hurl spores up to 30 feet away, where they swirl in a 10-foot cube for 1 minute. The spores disappear early if Morlin uses this feature again, if Morlin dismisses them as a bonus action, or if Morlin's Symbiotic Entity feature is no longer active.

Whenever a creature moves into the cube or starts its turn there, that creature takes Morlin's Halo of Spores damage, unless the creature succeeds on a DC 17 Constitution saving throw. A creature can take this damage no more than once per turn.

While the cube of spores persists, Morlin can’t use his Halo of Spores reaction.

Reactive Casting. Morlin casts one of the following druid or wizard spells that has a casting time of a reaction (spell save DC 17, if the spell is on both class lists, he may choose which ability score to use as the spellcasting ability):

2/day: counterspell

Halo of Spores. When a creature Morlin can see moves into a space within 10 feet of himself or starts its turn there, Morlin can use his reaction to deal 5 (1d10) necrotic damage to that creature unless it succeeds on a Constitution saving DC 17.

Fungal Infestation (5/Long Rest). If a beast or a humanoid that is Small or Medium dies within 10 feet of Morlin, he can use his reaction to animate it, causing it to stand up immediately with 1 hit point. The creature uses the zombie stat block in the Monster Manual. It remains animate for 1 hour, after which time it collapses and dies.

In combat, the zombie’s turn comes immediately after Morlin's. It obeys Morlin's mental commands, and the only action it can take is the Attack action, making one melee attack.

Grim Harvest. When Morlin kills a creature with necrotic damage, Morlin regains 9 (2d8) hit points.