This isn't directly about Halo 4, but it's still a suitable section. Now, I will be using wiki topics and posting them here for reference, learning, all that jazz.

Table of Contents

Section 1 - Spartan Program
Sub Section 1 - MJOLNIR
Sub Section 2 - Orion Program
Sub Section 3 - S II, III, IV Explanations


Section 2 - Non-Human Species (Excluding Ancient Humans) [WIP]
Sub Section 1 - Precursors
Sub Section 2 - Forerunners
Sub Section 3 - Kig'yar
Sub Section 4 - Sangheili
Sub Section 5 - San 'Shyuum
Sub Section 6 - Jiralhanae
Sub Section 7 - Mgalekgolo
Sub Section 8 - Yanme'e
Sub Section 9 - Unggoy
Sub Section 10 - Ancient Humans