What are those monsters on Relia's backpack called?

I noticed those cute monsters on Relia's backpack:

What are those called? Are they mentioned somewhere else in Star Ocean game itself?

Solution 1:

They are called Onigumo, which seems to be a popular mascot character in the Kingdom of Resulia.

リュックには“オニグモ”というレスリア王国で人気のマスコットが描かれている。
There's "Onigumo" on the back of the backpack, a popular mascot in the Kingdom of Resulia.

^{Famitsu.com (Japanese)}

There's also Onigumo strap on Miki's staff.

And an in-game item as a pre-order bonus

^{Onigumo strap accessory as a pre-order bonus from GEO Hyper Media Shop}

However, it's an original character for Star Ocean 5, it's not based on any games.

As for whether it's mentioned somewhere else or not, unfortunately I can't answer that since I don't play the game.