I looked a bit more into this. The following is from several wiki pages,
a collection from second edition "Demihuman Deities" and third edition "Faiths and Pantheons".
"Sword Dancers of Eilistraee
Specialized clerics are known as Sword Dancers of Eilistraee. They are excellent dancers and have the ability to use the sword in a unique fashion: through an agile, acrobatic and almost artistic swordplay, they can fight in such a graceful way to resemble a dance. To become a Sword Dancer, a drow has to spend at least 1 month on the surface, dancing each moonlit night for Eilistraee, and has to witness dawn at least once. The sword dancers lead the missions to find, help and protect any drow looking to return to the surface (or that can be made to return) and join a different life. They are skilled diplomats, especially active near elven and other races' settlements, working to establish peace and cooperation between the drow and the surface dwellers.
These priestesses also have various unique magical powers, granted to them by their goddess. They can form a particular bond with their sword, which allows them to infuse the weapon with Eilistraee's magic. They can imbue it with a variety of magical enhancements, let it sing like a singing sword (making them strike with increased precision and rallying their hearts), or let it dance (like a dancing weapon) to attack the enemy on its own or to protect the priestess.
The Sword Dancers have the ability to cast the magic missile spell, or to use its energy to empower their next sword strike, surrounding their blade with blue-white flames. They can also use their magic to temporarily enchant a bladed weapon with a silvery glow that increases the precision of its strikes, without the possibility of it being dispelled.
The Sword Dancers can sing and dance to channel the power of Eilistraee, and have the ability to sing their magic even amidst the chaos of the battle, while dodging and dancing around or while wounded. This magic is known as Spellsong. They can also manifest Eilistraee's moonfire at will.
Other magical abilities of these specialized priestesses were the capacity to cast spell turning, commune, true seeing, stone telling and plane shift. "
So with all this in mind i think we have to multiclass with cleric as base (war domain?), have decent charisma and then go into sword bard and maybe also sorcerer. But what about all the fighter goodies.. It's a tough build to pull off in 5e/BG3.
