Extraordinarily powerful creatures possess exploitable weaknesses, and well-prepared PCs learn about them before charging into the fray.

These creatures aren’t dumb. They recognize their own weakness. Some cultivate relationships with less powerful creatures to help offset those weaknesses. They offer protection or treasure in exchange for the lesser beings’ useful abilities.

These lesser beings are called “rider monsters.” Rider monsters add a wrinkle in combats against boss monsters. They force PCs to deal with the minor threat until they can negate the advantages granted by these weaker combatants.

Lichmote

This globe of light bobs about as it flies. Close examination of the globe reveals blasphemous images contained with it.

Drawn to Magical Might. Lichmotes, named for their association with liches, hail from worlds where magic has mostly died or become so chaotic no creature can wield it. They slip through dimensional rifts or portals to other worlds where they seek out powerful spellcasters, typically archmages or liches. Lichmotes encourage these new masters to delve into unknowable spells, through which the casters might recreate the calamities that devastated the lichmotes’ previous habitations.

Innocuous Helpers. Since lichmotes appear as globes of light from a distance or under cursory scrutiny, they often attach themselves to wands, staves, and other magical accoutrements belonging to their masters. This permits them to stay close enough to absorb threatening radiant energy or to replenish their masters’ reactive powers.

Two Lives. Lichmotes are eager to escape the worlds they help bring to destruction, as their deaths cause them to return as undead will-o’-wisps, physically withered from their living forms. Liches aided by the aberrations sometimes snuff them out prematurely when their usefulness as living defenders fades. Oddly, this seeming betrayal doesn’t diminish their loyalty to their masters.

Independent Lichmotes. Lichmotes don’t always attach themselves to powerful spellcasters. Those that choose a solitary path settle in isolated locations where they ally with will-o’-wisps. Some lichmotes search for nascent spellcasters, whom the lichmotes convince to pursue ever greater power, culminating in their apotheosis to lichdom. These lichmotes use their ability to locate magic to guide their “pupils” to scrolls and other items befitting the spellcasters’ station.

LICHMOTE             CR 5

Tiny Aberration

Armor Class 15
Hit Points 105
Speed 0 ft., fly 40 ft. (hover)
Perception 13    Stealth 15
Resistant necrotic | Aberrant Resilience
Immune lightning, radiant | blinded
Senses darkvision 60 ft.
Languages Common

STR	DEX	CON	INT	WIS	CHA
−2	+5	+3	+1	+4	+0

Aberrant Resilience. The lichmote is resistant to the charmed, frightened, paralyzed, and stunned conditions, and it has advantage on saves against spells or effects that would alter its form.

Illumination. The lichmote sheds bright light in a 10-foot radius and dim light for an additional 10 feet.

Radiant Absorption. Whenever the lichmote is subjected to radiant damage, it takes no damage and regains HP equal to half the radiant damage dealt.

Sense Magic. The lichmote senses and can pinpoint the location of magic within 120 feet of it. If it senses magic and can see the creature or object bearing the magic it senses, it sees a faint aura around that creature or object.

Unwelcome Return. If the lichmote is reduced to 0 HP, it rises one round later as a will-o’-wisp.

ACTIONS

Multiattack. The lichmote makes two Blinding Slam attacks. It can replace one of these attacks with a Disrupting Beam attack.

Blinding Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 7 (1d4 + 5) bludgeoning damage plus 13 (3d8) radiant damage, and the target must succeed on a DC 14 CON save or be blinded for 1 minute. The target can repeat its save at the end of each of its turns, ending the effect on itself on a success.

Disrupting Beam. Ranged Spell Attack: +7 to hit, range 60 ft., one target. Hit: 17 (3d8 + 4) radiant damage, and the target has disadvantage on its next save.

REACTIONS

Intercept Radiance. If the lichmote is within 30 feet of a creature that it can see and has been targeted by an attack, effect, or spell that deals radiant damage, the lichmote can draw some of that energy to itself. The target gains resistance to radiant damage until the beginning of the lichmote’s next turn. When the target takes radiant damage, the lichmote is subject to the same amount of damage, which triggers its Radiant Absorption.

Painful Restoration. If the lichmote is within 30 feet of a creature that it can see and has used its reaction, it can impart some of its energy to that creature. The lichmote takes 5 (1d10) psychic damage and allows the target to use that reaction again until the beginning of its next turn. The affected creature can only benefit from Painful Restoration once until the following dusk.