Large construct, lawful neutral

Armor Class: 17

Hit Points: 316

Speed: 30 ft , fly: 30 ft , swim: 30 ft , can hover

STR

18 +4

DEX

15 +2

CON

17 +3

INT

18 +4

WIS

16 +3

CHA

14 +2

Saving Throws: INT +8, WIS +7

Skills:

Perception +11

Damage Resistances: Lightning, Psychic

Senses:

Truesight 120 ft., Passive Perception 21

Languages: All, Telepathy 120 ft.

Challenge Rating: 12 ( 8400 XP)

Proficiency Bonus: +4

Actions

Multiattack. The septon makes four Tentacle attacks and uses Lightning Network or Spellcasting.

Tentacle. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) piercing damage, and if the target is a Medium or smaller creature, it has the grappled condition (escape DC 14). Until this grapple ends, the septon can’t use this tentacle against other targets. The septon has seven tentacles, each of which can grapple one target.

Lightning Network. The septon conjures a field of electricity that fills a 30-foot cube originating from itself before dissipating. Each creature in that area must make a DC 16 Dexterity saving throw. On a failed save, a creature takes 33 (6d10) lightning damage and has the stunned condition for 1 minute. On a successful save, a creature takes half as much damage only. A stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.