Brothers in Stone (Stone Soldiers #2) by C.E. Martin
Colonel Mark Kenslir is cursed to live forever, trapped in a young body, endowed with super human strength and an immunity to magic. Since the 1960s he has fought the supernatural and paranormal, protecting America while watching his comrades-in-arms grow old and die.
Now the last of the super soldiers, Kenslir must train a new generation of parahumans to fight alongside him and protect the United States from the magical and mythical.
BOOK 2: BROTHERS IN STONE
The shapeshifting Antedeluvian giant Ketzkahtel is back from the dead, once again tearing out and eating the hearts of American citizens.
Colonel Mark Kenslir will need the help of a new generation of stone soldiers and one brave girl to track down and stop the giant before it amasses enough power to become unstoppable.
Unfortunately for Kenslir, the giant is no longer alone. He’s resurrected his twin brother and the two giants decide to take the fight to the Colonel.