Cinder Wraith

Cinder Movement. The wraith can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object. A creature that touches the Cinder Wraith or hits it with a melee attack while within 5 feet of it takes 5 (1d10) fire damage. In addition, the Cinder Wraith can enter a hostile creature's space and stop there. The first time it enters a creature's space on a turn, that creature takes 5 (1d10) fire damage and catches fire; until someone takes an action to douse the fire, the creature takes 5 (1d10) fire damage at the start of each of its turns.

Illumination. The Cinder Wraith sheds bright light in a 10-foot radius and dim light in a 30-foot radius.

Cinder Cloud. The area around the cinder wraith is lightly obscured, any creature that start's or ends its turn within 5 ft. of the cinder wraith takes 5 (1d10) fire damage.  

Multi-attack. The Cinder Wraith makes two Spark Drain attacks 

Spark Drain. Melee Weapon Attack: +8 to hit, reach 5 ft., one creature. Hit: 21 (4d8 + 3) Fire damage. The target must succeed on a DC 14 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. plus catches on fire, a creature on fire needs to use an action to douse itself otherwise it takes an extra  5 (1d10) of fire damage per turn. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. 

Create Elemental (1/day recharge). The Cinder Wraith targets an open flame. A number of smoke mephit's come out, roll 1d8+1. The smoke mephit's rise out of the space of the open flame or in the nearest unoccupied space. The Mephit's is under the wraith's control.