Why?
“The fool, with all his other faults, has this also, he is always getting ready to live.” – Epicurus
The particle の is your second particle, and it’s fairly noun-specific as well. This particle will let you use what you learned in the “Identity” chapter and alter it so it’s more useful, changing the way you can identify things (now something can belong to something else).
This chapter also helps you to review Season 2 (because we use everything from Season 2 in this chapter) and it gets you going on your second particle (you gotta learn them all, eventually)!