First Strike. The reckoner has advantage on initiative rolls.

Spellcasting. The reckoner is a 5th-level Boros spellcaster. Its spellcasting ability is Intelligence (spell save DC 12, +4 to hit with spell attacks). The reckoner has the following wizard spells prepared:

Cantrips (at will): blade ward, light, message, shocking grasp, encode thoughts, mage hand

1st level (4 slots): guiding bolt, shield, thunderwave, witch bolt, disguise self, [spell]sleep[/sleep]

2nd level (3 slots): blur, levitate, detect thoughts, pass without trace

3rd level (2 slots): lightning bolt, nondetection, meld into stone, gaseous form

Longsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) slashing damage, or 8 (1d10 + 3) slashing damage if used with two hands.

Spies' Murmur. Can allow another known person within 1 mile wearing a Spies' Murmur to hear everything you hear for 1 hour. Can end this effect as a bonus action, and it ends if incapacitated.

Lightning Backlash (Recharge 5–6). When a creature hits the reckoner with an attack, the attacker takes lightning damage equal to half the damage dealt by the attack.