HAP P Y Happy has been with Natsu ever since he was hatched from an egg; the two are barely separated and have a bond that of family. The two share a house and know each other better than anyone.
LUCY HEARTFILIA Natsu and Lucy share a very close relationship, as it was Natsu who brought Lucy to Fairy Tail. Natsu thinks of Lucy as a very nice person and one of his closest friends. Natsu has a tendency to break into Lucy's house during various points of the day, much to her annoyance.
ERZA SCARLET Erza and Natsu share a very close bond. Initially described as frightful and omnipotent, Natsu nonetheless admires her strength, determination and courage. Their relationship has not changed over time, and the two would readily protect each other. Erza acts as a mediator when Gray and Natsu fight.
GRAY FULLBUSTER Natsu and Gray are teammates that have had a close and rivalled relationship and as such usually start a fight whenever they see one another. The two truly care for each other, and would do anything in order to protect each other.
WENDY MARVELL
Two fellow Dragon Slayers, Natsu and Wendy are close friends and guildmates, united by their wish to find their Dragon foster parents. Wendy has healed Natsu's injuries several times through the use of her Magic; they have a friendly bond.