Castrum Omega

Immutable Form. The castrum is immune to any spell or effect that would alter its form.

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

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

Magic Weapons. The castrum’s weapons are magical.

Siege Monster. The castrum deals double damage to objects and structures.

Fragile Limbs. The castrum’s four limbs individually have an HP bar (exactly 500 HP each). Upon defeating a limb, the castrum takes 300 damage (the HP lost can not be restored by any means unless under repair) and is restrained and incapacitated for 2 rounds. During this time, all attacks dealt upon the castrum will deal twice the damage. Each limb is vulnerable to all attack types (except the types in which the castrum is immune to), but they are also immune to all conditions. The hind limbs can only be broken during the charging time for Castellum Impulsum, while the front limbs can not be broken during that time. If the hind legs are broken, instead of 2 rounds, it will be restrained and incapacitated for 3 rounds.

Multiattack. The castrum makes 2 melee attacks and 2 ranged attacks.

Death Arrow. Melee Weapon Attack: +17 to hit, reach 14 ft., one target. Hit: 2d10 + 10 piercing damage and 1d8 necrotic damage.

Luminous Impact. Ranged Spell Attack: +17 to hit, range 14/140 ft., one target and all targets near 5 ft. of target. Hit: 2d10 + 15 radiant damage.

Castellum Impulsum. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 5d10 + 100 bludgeon damage. This attack needs 4 turns before hitting the target. During that time, the target is restrained, and the castrum is incapacitated and also restrained. The attack will be interrupted once a hind limb is broken, and the damage will be halved once both front limbs are broken.

The castrum 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 castrum regains spent legendary actions with each successful critical attack.

Aegis (Costs 2 Actions). Guarantees the next attack will be halved.

Arrow Volley. The castrum can use two Ephemeral Arrows, each directed at a different target.

Cannonball Volley. The castrum can use two Ephemeral Flares, each directed at a different target.