Elfman is an 18-year-old mage and one of Fairy Tail's physically strongest fighters. He's best known for his "Take Over" magic, which lets him absorb the powers of defeated monsters into his right arm—a skill that earned him the nickname "Beast Arm Elfman." His guild mark is on his neck.
He's got top-tier magical ability, but there's a tragedy behind his current limitations. Years ago, a full-body Take Over transformation went catastrophically wrong, and Elfman lost control of himself. His younger sister Lisana, who was also a Fairy Tail member, sacrificed her life to break his concentration and snap him back to reality. The loss devastated him and his older sister Mirajane. Now whenever Elfman tries to attempt a full-body Take Over, the memory of Lisana floods back, shattering his focus and causing the spell to collapse. It's clear the trauma of losing her has left deep scars—fans often note that his heart seems genuinely closed off because of what happened.
On the surface, though, Elfman comes across as enthusiastic and loud, constantly rambling about manliness and what it means to be a "real man." His speeches about manhood are frequent and often pretty nonsensical, but it's kind of his thing.
Content compiled by AnimeList.moe from publicly available sources.