Hansen's Raiders, USMC
All marine raider battalions were disbanded in February 1944. Personnel were used to organize the "new" 4th Marine Regiment (the "old" 4th Marines had surrendered at Corregidor in Spring 1942) and the newly-constituted 5th Marine Division. No raiders, as such, fought at Iwo Jima.
Raider Battalions were known informally by the names of their respective commanders: 1st Battalion = Edson's Raiders (Merritt A. Edson), 2d Battalion = Carlson's Raiders (Evans F. Carlson), etc. I find nothing on a battalion commander named Hansen or Hanson - which may or may not be significant.
Fifth Marine division - especially 28th Marines - had a large number of former raiders among its ranks. At least three of the five marines who raised the flag over Mount Suribachi - including PFC Ira H. Hayes - were former raiders. Also, at least three of the twent-six men who won the Medal of Honor at Iwo Jima were former raiders.