Chadwick

Conjuured Illumination. Chadwick, as a bonus action, can shed either dim light in a 15-foot radius, or bright light in a 15-foot radius and dim light for an additional 15 feet. It can switch between the options or diminish the light as an action.

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

Rejuvenation. If Chadwick is destroyed, it regains all its hit points in 1 hour unless holy water is sprinkled on its remains or a dispel magic or remove curse spell is cast on them.

Special Equipment. Chadwick uses following items: Greatsword +1, Circlet of Human Perfection, Helmed Horror's Plate Armor, Gauntlets of Ogre Power.

Spell Immunity. Chadwick is immune to following spells: Banishment, Slow, Confusion.

Spellcasting. Chadwick is a 5th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 14, +6 to hit with spell attacks). It requires no somatic or material components to cast its spells. The flameskull has the following wizard spells prepared:

Cantrip (at will): mage hand, green-flame blade, control flames

1st level (4 slots): magic missile, shield, false life

2nd level (3 slots): blur, flaming sphere, aganazzar's scorcher

3rd level (2 slot): fireball, ashardalon's stride

Multiattack. Chadwick uses Fire Ray twice or attacks twice with his Greatsword.

Fire Ray. Ranged Spell Attack: +6 to hit, range 30 ft., one target. Hit: 13 (3d6+3) fire damage.

Greatsword. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 10 (2d6+5) slashing damage. Chadwick can use Green-Flame Blade with this attack, dealing additional 5 (1d8) fire damage to the target and 8 (1d8+3) to another creature within 5 feet of that target.