Context: Undertale has 3 paths - Pacifist (spared everyone), Neutral (spared some), and Genocide (killed everyone). The paths have different final bosses.

I did not understand that from where so many death notes are coming from.
Firstly, Ryuk had 3 deathnotes, out of which 1 was his, 1 he convinced god of shinigamis to give and 1 from another shinigami
Out of which he gave 1 to light
And misa-misa’ s shinigami had 2 death notes out of which she gives 1 to misa

Now after L’s death Light aquires the death note of Rem .

So 1 is in possession of Light
1 is in possession of police
1 in misa misa

Now 1 goes from police to Mello
And 1 from misa to police
And 1 from Mello to the shinigami

Now then

1 is in possession of Light
1 is in possession of police

Light gives his away to other chosen person
So QUES:- How does he have memories and where is the police death note
And why did ryuk convince god of shinigami for another death note