Maybe, maybe not. Blockchain itself is a decentralized database. --That means it's not hosted in any one particular place, so it's gonna be really hard to kill.
--Each block in the chain is encrypted in such a way that it can't be tampered with, or counterfeited, so no stealth edits.
--Even trying to delete a block will cause the blockchain to become invalid, and a well-designed one can repair itself by reconstructing deleted blocks.

Two things blockchains really suck at are random access to data (think finding a song on a cassette tape vs. a CD) and hosting large chunks of binary data- cryptographic operations are CPU-intensive, and get a lot worse when the data is big.

I think most likely, what's on the blockchain is an Index. Could be magnet links to torrents of the whole thing, a URL to a piece of the data, some ip addresses of dormant machines waiting for someone to connect. There might be some pics or PDFs on the blockchain, but I doubt the corpus is there.

Can the DS get to it first? Tough question. Think of it like the movie "Ready Player One". First one to the keys wins the prize.