Hi.
It is explained in the dictionary that “autos” simply stands for the demonstrative pronoun (he, she, it) whe it is in oblique case.
But I am vague.
Does the oblique case here include accusative ?
(I saw in a grammar that accusative is erected case as well as nominative.)
hi junya, yes the reference to oblique cases of αὐτός there includes the acc.
in other contexts you do sometimes have a distinction between (1) gen. and dat. and (2) nom. and acc. (e.g. for accentuation of some nouns)-- and perhaps some books refer to the first group of gen. and dat. as “oblique”, which is what is confusing you – but that’s not what’s meant here. cheers, chad 
Thank you, Chad.