(CNN) Navy SEAL Charles Keating IV, the grandson of savings-and-loan financier Charles Keating Jr.,died in combat against ISIS in northern Iraq, his family said Tuesday.

"He is our family hero in every sense of the word," cousin Elizabeth Ann Keating told CNN.

Keating, 31, is the third American combat casualty since the U.S. redeployed forces to Iraq in the summer of 2014 to advise local forces and conduct special operations against ISIS. He was an adviser to Kurdish Peshmerga forces fighting ISIS, Pentagon spokesman Peter Cook said in a statement Tuesday.

He died as a result of a "coordinated and complex attack" by roughly 100 ISIS fighters nearly 30 kilometers (18.6 miles) north of Mosul, Pentagon officials confirmed Tuesday.

"This sad news is a reminder of the dangers our men and women in uniform face every day in the ongoing fight to destroy ISIL and end the threat the group poses to the United States and the rest of the world. Our coalition will honor this sacrifice by dealing ISIL a lasting defeat," Cook said, using another term for ISIS.

Defense Secretary Ash Carter confirmed the reports while speaking to reporters in Germany, adding that the death shows "it's a serious fight that we have to wage in Iraq."

Keating came from a long line of devoted service members, going back to his namesake, great-grandfather Charles Keating, who served in World War I, and grandfather, Charles Keating Jr., a naval pilot in World War II.

Charles Jr. rose to prominence in the mid-20th century as a lawyer and businessman who made millions in Phoenix real estate before he was implicated in the $150 billion savings-and-loan crisis that..read more at CNN