Hey guys! Your pal CoNsTiPaTiOnGuY here with all the ranks up to inheritor! I myself am a Captain Grade 1 at the time, but here are all the ranks that came with the new update. (All the ranks up until 2012, which makes sense unless you are from the future.) Without further ado, here is the current 2012 ranks in Halo Reach. Enjoy!
Recruit
Private
Corporal (Achievment unlocked when reached)
Corporal grade 1
Sergeant
Sergeant grade 1
sergeant grade 2
warrant officer
warrant officer grade 1
warrant officer grade 2
warrant officer grade 3
captain (achievment unlocked when reached)
captain grade 1
captain grade 2
captain grade 3
major
major grade 1
major grade 2
major grade 3
lt. colonel
lt. colonel grade 1
lt. colonel grade 2
lt.colonel grade 3 (old highest rank)
commander
commander grade 1
commander grade 2
commander grade 3
colonel
colonel grade 1
colonel grade 2
colonel grade 3
brigadier
brigadier grade 1
brigadier grade 2
brigadier grade 3
general
general grade 1
general grade 2
general grade 3
general grade 4
field marshall
hero
legend
mythic
noble
eclipse
nova
firerunner
reclaimer
INHERITOR (highest rank)
I hoped this helped, thanks and check out my other posts!