Fey Ancestry. The bladesinger has advantage on saving throws against being charmed,  and magic can't put it to sleep.

Victorious Blades. The bladesinger's melee weapon attacks are magical, and it adds its Intelligence modifier to the weapon's damage (included in the attack).

Bladesong. While the bladesinger isn't wearing Medium or Heavy armor or using a shield, its AC includes its Intelligence modifier, and it has advantage on Constitution saving throws made to maintain concentration on a spell.

Spellcasting. The bladesinger elite is a 7th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 16, +8 to hit with spell attacks). The bladesinger elite has following wizard spells prepared:
Cantrips (at will): fire bolt, shocking grasp
1st level (4 slots): shield, absorb elements, longstrider 
2nd level (3 slots): flaming sphere, blur, misty step
3rd level (3 slots): Lightning Bolt, Counterspell, Dispel Magic
4th level (1 slot): Greater Invisibility

Multiattack. The bladesinger elite makes two attacks with its rapier.

Rapier. Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit:  12 (1d8 + 8) slashing damage.