Well, it depends.
If it's on the field by itself, then no.
It's effect means that every time you send a card from the deck to grave with another lightsworn, you can send two additional cards to the grave. So, for example, if you have Lumina, Lightsworn Sorceress on the field with Garoth on the field, then at the end of the turn, you have to send two cards from the deck to the grave, for Lumina's effect. Now that another lightsworn has caused you to send cards to the grave from deck, you must send an additional 2(two more) to the graveyard.
~Aster Phoenix