Porlyusica

Polyushka is a lonely old healer living in a forest outside of Magnolia town. She is withdrawn and reclusive because she doesn't like humans, suggesting she might not be one herself. However, she appears to always come to Makarov's aid suggesting he is an exception to her hatred.

Background
Porlyusica was once, and still is given how she looks in her advanced age, a beautiful woman who worked alongside Makarov. However, one day she left by herself and went into a hermit lifestyle.

One time, Makarov took Erza Scarlet to her so that she could heal Erza's eye. After she was done, she notices that she did something wrong because Erza could only cry out of one eye. Erza laughed it off saying she already shed half her tears anyway.

Phantom Lord arc
When Makarov gets injured after the Phantom Lord Guild battle by Aria, the guild members take him to Polyushica to be healed. She appears to be an old friend of his. However, she chases Alzak Cornell and Bisca Mulan out after they drop him off. She says that Makarov could recover faster, but Makarov's magical energy is floating around the air and can't be retrieved. Mystogan however, recovers it later through his own wind magic and Makarov recovered faster. She scolds Makarov for fighting at his age and Mystogan for leaving an apple core on the ground.

Fighting Festival arc
Porlyusica appears at the guild amidst the fighting, asking where Makarov is. After Levy McGarden informs her, she completely ignores Levy and heads straight toward Makarov. With just a glance at him, she asks Levy to bring Laxus Dreyar over, stating that he doesn't have long to live. She later leaves Magnolia Town having healed Makarov. Before leaving she overheard that people idea that Laxus would be the next Fairy Tail master but she silently scoffs at the idea.

Trivia

 * "Polyushka" is a very slightly misspelled Russian word (it's "pOlyushko" in russian), it means "a wide field" in the poetic and somewhat "fairy-taileish" style. This makes the old woman the third person with a Russian-based name, along with Makarov and Ivan Dreyar. It is also a kindly variant of the female name - Polina (eng. Pauline)