Been playing for a while now and got a hang for the system, but one thing that still puzzles me is, can the stats be raised or is it like AD&D where you play the character you rolled from start to end?

All stats can be raised in several ways. But good starting stats can help a lot during the first parts of the game.

Could you elaborate how, only way I know how is by secondary skill trainers?
At the moment I'm level 7 and raking a lot of money in the Monster Bowl Arena of the second town.

*** Spoilers following***





For each stat there's a location. When you enter it this stat will be raised by 10 if it's lower than 50. (change not visible before resting). You can visit those locations several times (leaving and reentering resets the dungeons) to raise it above 50.
There are also locations where you can trade 5 points in a stat for 3 in another and the circus is also a way to improve stats.

2 hints about the location you want :

In the cave below Vulcania is the +10 endurance boost.
In the cave below Sansobar you can raise thievery by +10.
Both repeatedly until >49.

The other +10 locations are in other dungeons, just keep exploring. High endurance grants more HP at level up but the other stats don't pay interest if you raise them early, so just be patient, you will find them.

kmonster points out some of the ways to raise stats in his post, below the spoiler warning. Those are the easiest ways to raise stats, but there is another way too:



*** Spoiler alert ***





As you explore the world, you may come across fragments of messages. Write these down, and when you've assembled and decoded the messages you'll find instructions for another way to raise your stats.






**** End spoilers ***