Aegis

Form Change. The Aegis can swap between Blade mode and Shield mode as a bonus action. Each form has special traits for the Aegis.

Blade Mode. The shields surrounding the Aegis split into four sharp blades which proceed to spin around the Aegis. Whilst in Blade mode, the Aegis's speed increases by 10 feet and can attack perform a full round of attacks.

Shield Mode. The blades merge into two shields, which spin slowly around the Aegis. Whilst in Shield mode, the Aegis's AC increases by 3 but it's speed decreases by 10 feet. In addition, all damage it takes is reduced by its Consitution modifier. 

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

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

Magic Weapons. The Aegis's weapon attacks are magical.

Antimagic Susceptibility. The Aegis is incapacitated while in the area of an antimagic field. If targeted by dispel magic, the Aegis must succeed on a Constitution saving throw against the caster's spell save DC or fall unconscious for 1 minute.

Multiattack. If the Aegis is in Blade Mode, it can make four Slash attacks. If the Aegis is in Shield Mode, it can only make two Bash attacks.

Slash (Blade Mode Only). Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) slashing damage. 

Bash (Shield Mode Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) bludgeoning damage. If the target is medium or smaller, it must make a DC 14 Strength saving throw or be knocked prone.

Block (Shield Mode Only). The Aegis can spend its reaction to move a shield to block an incoming melee or ranged attack against itself on another creature within 5 feet of the Aegis. The Aegis can increase the targets AC by 2 against the attack.