Weave Wisp

Ephemeral. The wisp can't wear or carry anything.

Incorporeal Movement. The wisp 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.

Variable Illumination. The wisp sheds bright light in a 5- to 20-foot radius and dim light for an additional number of feet equal to the chosen radius. The will-o'-wisp can alter the radius as a bonus action.

Don't Go Into the Light. Once per long rest, the Wisp can call upon greater fey to revive a fallen ally. The wisp passes through a creature that has died within the last minute. That creature returns to life with 1 hit point. Other effects such as restoration of limbs, further healing, cleansing of curses or poisons etc are at DM discretion and may incur a debt to the intervening fey.

Consume Life. As a bonus action, the wisp can target one creature it can see within 5 feet of it that has 0 hit points and is still alive. The target must succeed on a DC 15 Constitution saving throw against this magic or die. If the target dies, the wisp regains 10 (3d6) hit points.

Invisibility.  The wisp and its light magically become invisible until it attacks or uses its Consume or Don't Go, or until its concentration ends (as if concentrating on a spell).

Shock. Melee Spell Attack: +11 to hit, reach 5 ft., one creature. Hit:  (4d8)+9 lightning damage.

Winter Court's Chill. As a bonus action, the Wisp may pull the warmth from the air around it in a 5 ft radius. Creatures that enter the area for the first time on a turn or start their turn there must make a DC15 Constitution save or take 2d6 cold damage. A creature that makes a successful save takes half. This effect is maintained as though the wisp is concentrating on a spell for a duration up to a minute.