Chainbearer

Legendary Resistance (3/Day). If the chainbearer fails a saving throw, it can choose to succeed instead.

Magic Resistance. The chainbearer has advantage on saving throws against spells and other magical effects.

Innate Spellcasting. The chainbearer's innate spellcasting ability is Charisma (spell save DC 18), +10 to hit with spell attacks). It can cast the following spells, requiring no material components:

At will: greater restoration (self only), mage hand, rope trick (the opening to the extradimensional plane expands to accommodate creatures up to huge size and the space can hold up to 2 huge creatures).
1/day each: commune, dispel evil and good.

Multiattack. The chainbearer makes 2 chain whip attacks, each of which can be replaced by a fling. The chainbearer also flings one object or creature it has grappled by a chain.

Chain Whip. Melee Weapon Attack: +10 to hit, reach 30 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage plus 7 (2d6) radiant damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. The chainbearer has 6 arms for holding chains, each of which can grapple one target.

Fling. One Large or smaller object held or creature grappled by the chainbearer is thrown up to 25 feet in a direction of the chainbearer's choice and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 18 Dexterity saving throw or take the same damage and be knocked prone.

Embedding of the Chain. The chainbearer instantaneously embeds a chain into the earth in a location that it can see. This does not cause damage to any creatures or structures. The chainbearer may instead instantaneously remove a chain that it can see from the earth.

Shaking of the Chain. The chainbearer casts the spell earthquake centered on an embedded chain it can see within 500 feet. Treat this spell as though it is not magical so it cannot be countered by antimagic. 

Lowering/Raising of the Chain. The chainbearer chooses an embedded chain it can see within 120 feet of it and raises or lowers an area of terrain no larger than a 40 feet circle centered on the chain. The terrain can be lowered or raised by no more than 40 minus the chosen circle radius. The chainbearer can choose this terrain change to be cliff-like or smooth. If the chainbearer chooses it to be cliff-like, a structure on the fault line of the circle automatically collapses. If the chainbearer chooses it to be smooth, structures in the area and on the fault line take 50 damage as do roofs that are struck by the raising earth. Follow rules in the earthquake spell for collapsing buildings. If a concentrating creature is within the area of effect, it must make a Constitution saving throw. On a failed save, the creature's concentration is broken. All creatures in the area of effect must succeed a dc 18 dexterity saving throw or the creature is knocked prone. If a creature in the area fails their dexterity saving throw and strikes a solid surface by the raising earth, it takes 14 (4d6) bludgeoning damage for every 10 feet the earth is raised beneath you, otherwise they take half damage.

The chainbearer can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The chainbearer regains spent legendary actions at the start of its turn.

Chain Whip. The chainbearer makes one chain whip attack.

Fling. The chainbearer flings one object or creature it has grappled by a chain.

Embedding of the Chain. The chainbearer uses embedding of the chain.