False Appearance. While the skeleton remains motionless and isn't exposed to bright light, it is indistinguishable from a normal skeleton.

Sunlight Sensitivity. While in sunlight, the skeleton has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Multiattack. The skeleton makes two longsword attacks.

Longsword. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (1d8 + 3) slashing damage.

Parry. The skeleton adds 2 to its AC against one melee attack that would hit it. To do so, the skeleton must see the attacker and be wielding a melee weapon.

Shield Bash (Recharge 5-6). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: The target must succeed on a DC 15 Strength saving throw or be knocked prone.

Defensive Stance. When a creature the skeleton can see targets it with an attack, the skeleton can impose disadvantage on the attack roll against the target if the attacker is within 5 feet of the skeleton (provided the skeleton isn't incapacitated). The skeleton must be wielding a melee weapon.

Equipped with full plate armor, Abraham becomes an even more formidable defender, capable of withstanding attacks while protecting the archmage necromancer. Feel free to adjust any details to fit the specific needs of your campaign.