Jerome is a fairly tall blond man. He uses a black sword with Black Magic for battles.
Like other Avatar members he is a Zeref fanatic. He is one of the ones to suspict Gray for being a spy, who uses it as a chance to tell him his story. When Natsu and Lucy breaked in the Avatar base, he is the last one to confront them and threakens to kill the already incapacitated Lucy with his sword. When "Operation Purification" starts he still suspects Gray for being a spy and begins to lose his cool when he sees Gray fighting against Avatar. He then decides to fight Erza and leaves his fellow cultists to the others. In the fight he managed to destroy all but one of Erza's swords, but was defeated by Erza's ability to slash people without them noticing it. After Natsu destroyed Ikusa-Tsunagi he was left in disbelief that it could be defeated. Short after he's arrested by the Custody Enforcement Unit who take him away.