Well, that's going to be more difficult than you might think - the fonts used in Trine 5 are created by us developers at Frozenbyte. So it's called the "Trine font" but it isn't and shouldn't be available publicly, at least not at the moment. (There are some language fonts which are not created by us, but I assume you meant the main English/European font.)

Sorry that the answer probably wasn't what you're looking for, however if you are looking for a "fantasy font" or a font similar to the font we use, perhaps you should look to find the "Argos" font. I believe that's the font we used in the first Trine in 2009 before we created our own fonts. I hope this helps.

- Joel, Frozenbyte team, developers of Trine 5