Birkus

Fey Step (Recharge 4–6). As a bonus action, the eladrin can teleport up to 30 feet to an unoccupied space it can see.

Innate Spellcasting. The eladrin's innate spellcasting ability is Intelligence (spell save DC 16) (+6 to hit modifier). It can innately cast the following spells, requiring no material components:
- At will: fog cloud, gust of wind, ice knife

- 1/day each: cone of cold, ice storm,  Investiture of Ice

- 1/week: storm of vengeance 

Magic Resistance: The eladrin has advantage on saving throws against spells and other magical effects.

Assassin's finesse: as a bonus action, Birkus can switch between any of his weapons

Sorrowful Presence: Any non-eladrin creature that starts its turn within 60 feet of the eladrin must make a DC 13 Wisdom saving throw. On a failed save, the creature is charmed for 1 minute. While charmed in this way, the creature has disadvantage on ability checks and saving throws. The charmed creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to any eladrin's Sorrowful Presence for the next 24 hours.
Whenever the eladrin deals damage to the charmed creature, it can repeat the saving throw, ending the effect on itself on a success.

Birkus can make 3 melee attacks; 2 attacks with 1 weapon and 1 attack with another.

Frozen dagger: Melee Weapon Attack: +8 to hit, reach 5 ft., one target. 1d4+6 cold dmg

- Attacks made with this dagger deal cold damage instead of piercing. If you score a critical hit with this weapon, the target must succeed on a Constitution saving throw (save DC 15) or be paralyzed until the end of its next turn, frozen in place and unable to move. If it succeeds, its movement speed is halved instead. 

Frost brand: Melee Weapon Attack: +8 to hit, reach 5 ft., one target. 1d6+6 slashing dmg & 1d6 cold dmg

- When you hit with an Attack using this magic sword, the target takes an extra 1d6 cold damage. In addition, while you hold the sword, you have Resistance to fire damage. In freezing temperatures, the blade sheds bright light in a 10-foot radius and dim light for an additional 10 feet. When you draw this weapon, you can extinguish all nonmagical flames within 30 feet of you. This property can be used no more than once per hour.

Ice Sickle: (sickle), Melee Weapon Attack: +5 to hit, reach 5 ft., one target 1d4+3 slashing dmg

-This magic sickle from the Everglacier is perpetually covered in tiny, needle-like icicles along its edge that reform after 12hrs. The icy needles dig into the wound, freezing and spreading throughout the body. The first target hit by this weapon takes 1d6 cold dmg at the start of each of your turns. the target can remove then needles with a dc 15 medicine check or stay near a heat source for 30 mins to melt the needles.  

Frigid Rebuke. When the eladrin takes damage from a creature the eladrin can see within 60 feet of it, the eladrin can force that creature to succeed on a DC 16 Constitution saving throw or take 11 (2d10) cold damage.