Astral Song (3/day). Xeleth is a Bladesinging Wizard, while the song is active the elf's AC and damage rolls increases by it's Intelligence modifier (included in attack).

Fey Ancestry. The elf has advantage on saving throws it makes to avoid or end the charmed condition on itself, and magic can’t put it to sleep.

Mobile. The elf does not invoke opportunity attacks from enemies he has attacked the current round. 

Special Equipment. The elf wields a +3 Star Razor.

Unusual Nature. The elf doesn’t require sleep.

Multiattack. The elf makes two Star Razor attacks or two Radiant Beam attacks (if available).

Star Razor. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 30 (5d6+13) radiant damage, once per turn the target is also targeted by the spell booming blade 7 (2d6) force damage,(+3d6 if the target moves on its next turn).

Radiant Beam (Recharge 4-6). A magical beam of radiance flashes out from the elf’s hand in a 5-foot-wide, 60-foot-long line. Each creature in the line must make a DC 18 Constitution saving throw, taking 17 (5d6) radiant damage on a failed save, or half as much damage on a successful one.

Spellcasting. The elf is a 14th level wizard and can casts one of the following spells, using Intelligence as the spellcasting ability: DC 18 +10

At will: fire bolt (3d10 radiant), booming blade (2d6+3d6 force)

1/Day each:flame strike, fly, mislead, sending

Starlight Step (3/Day). The elf magically teleports up to 30 feet, along with anything it is wearing or carrying, to an unoccupied space it can see.

Star Blade (1/Day). Xeleth uses his weapon to cast spiritual weapon (4th level - +10 3d8)

Summon Solar Dragon (1/Day). Xeleth magically summons an adult solar dragon named Nazyd, The Champion of Xaryxis. The summoned dragon appears in an unoccupied space that the summoner can see, acts during its summoner's turn , and is an ally of its summoner. It remains for 10 minutes, until it or its summoner dies, or until its summoner dismisses it as an action.

Light of Xaryxis. As a reaction to being hit by a melee attack Xeleth can cast shield that also pushes enemies 10 ft. away if this causes them to miss. 

Song of Defense (3/Day). As a reaction to taking damage Xeleth can expend spell slots to reduce damage by 20.