Being a Tiefling with Astarion.

[MailFist]

If you play as a tiefling, why cant you just tell astarionn what his back says as tieflings can read infernal?

[Gilli-chan]

Small spoiler You can and try, but it's only part of a larger piece so you can't say what it means in it's entirety, only that it's a contract.
Another spoiler for Act 2 Later you will meet Rafael again and Astarion will make a deal with him to learn what the whole contract says.
Hope this helps.